BULLPUP FORUM

Bullpup Rifles (Auto & Semi-Auto Centerfire) => IWI Tavor SAR & X-95 => Topic started by: ShootingSight on August 28, 2017, 07:12:14 PM



Title: Stronger recoil spring for suppressed Tavor
Post by: ShootingSight on August 28, 2017, 07:12:14 PM
There are two threads going, one called 'Any machinists here', and the other titled 'Hey IWI'.  Both discuss a stronger recoil spring for the Tavor, so when you shoot it suppressed the recoil is not so violent.

So I pulled my Tavor apart and measured the OEM factory spring, then ran spring calculations.
It is
0.050 wire
0.455 OD
19.125" free length
10" installed length
5.8" fully compressed length

I calculate the rate at 1.175lb/in
So it is under 10.7lb with the bolt closed, 15.6lb with the bolt open.

The guide rod is 0.343" diameter, what sucks is that the tube it fits in is 0.497" diameter.

I say 'sucks' because when I look at stock spring options, I found lots that are 1/2" OD, and of course the OD swells slightly as you compress it, so it would bind inside the piston tube.  This cuts down lots of options.

I ran calculations to see how we could stiffen it up, and looked at the total energy the spring would absorb.  I came up with options at +6%, +19%, and +25%, maybe a +32% (this might be a non-standard wire diameter), +40%, and +50%.  We are talking energy here, so the +50% means bolt closed force would be about the same as the bolt-open force is today.

Bad news is that with the limit on the OD I was not able to find stock springs.  I'll keep looking, but it looks like a custom spring run is $500 per option.

So the question is 'who is up for it'?  I'd propose we start with the +25% option.  We can always go down by cutting coils.  No going up without limiting bolt travel.

I'll throw $200 at the project, If we call the springs $50 each, I'd need 6 more people to sign up and buy one to make this a go.  Of course, if we guessed wrong, we are out the money.  Or if 10 people sign up at $30 ....  Happy to hear proposals.  I'd say 10 people at $30 would work, and then I'd keep the price at $50 if it does work.  That way the people who take the risk get a benefit.

Thoughts?


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: RabbitSlayer on August 28, 2017, 07:32:53 PM
I'm in, I'll specify the exact amount I'll pitch once we see how many people are willing to pitch in.

Thank you very much for your work regarding this subject, you found details that people like me would have no clue how to figure out.  Your work is appreciated.

Will this run of springs be one specific weight, or will we be able to try two different weights?
If trying only one weight for the first batch, I think the 25% would be a good place to start like you suggested.

Mods, we should sticky this thread.  I think once we figure out the right springs, a ton of more guys will want to buy Tavors to run cans on them.



Title: Re: Stronger recoil spring for suppressed Tavor
Post by: ShootingSight on August 28, 2017, 07:43:35 PM
Unfortunately, the cost is per option.  The cost in springs is the machine setup.  For them, the actual cost per spring is small, but the base cost to set up and tune a machine is the bulk of the cost unless you are making thousands of springs.

I'd say let's let this thread run for a while and see the interest.  If it looks like enough, we can start a poll to collectively chose an option.  You might be on to something.  Enough people shoot the Tavor suppressed (especially now with the 300BLK option starting to ship) that there is a market out there.

I wonder if the 300BLK kit comes with a new recoil spring?


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: RabbitSlayer on August 28, 2017, 07:58:23 PM
Unfortunately, the cost is per option.  The cost in springs is the machine setup.  For them, the actual cost per spring is small, but the base cost to set up and tune a machine is the bulk of the cost unless you are making thousands of springs.

Makes sense.  So I assume you would be paying a third party to make the springs to the specs you ask?

Also, you mentioned earlier that if the spring weight is too heavy we could soften them by cutting a coil or two..  I'm sure we could get the first batch to work through trial and error pretty easily.  If 25% is too strong, maybe you or someone could calculate exactly how many coils softens the spring by what percent.
I like where this is going, I'm exited  ;D 
I've heard a few guys complain about cycling issues with a suppressor on their Tavor, so this could fix that.
Even though masking tape has cured any gas in face problems I've had, this would also help a ton.  Most gas I noticed leaks through the rear of the optics rail near the rear sight.



Title: Re: Stronger recoil spring for suppressed Tavor
Post by: RabbitSlayer on August 28, 2017, 08:00:21 PM
I wonder if the 300BLK kit comes with a new recoil spring?

I wouldn't be surprised if it had a different spring weight, probably even softer than the 556 Tavor since it has an adjustable gas block for subsonic ammo.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: AZ-Chris on August 28, 2017, 08:40:04 PM
Count me in on this.


Title: Re:
Post by: Hit Factor on August 28, 2017, 08:47:21 PM
I'm in.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: l2a3 on August 28, 2017, 11:35:14 PM
Am I correct in believing that this "New" recoil spring will work in both the SAR & X-95 when suppressed?
Thanks for any reply.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: RabbitSlayer on August 29, 2017, 12:21:26 AM
Am I correct in believing that this "New" recoil spring will work in both the SAR & X-95 when suppressed?
Thanks for any reply.

Yes, SAR and x95 use the same spring.



Title: Re: Stronger recoil spring for suppressed Tavor
Post by: ShootingSight on August 29, 2017, 08:22:11 AM

Makes sense.  So I assume you would be paying a third party to make the springs to the specs you ask?

Also, you mentioned earlier that if the spring weight is too heavy we could soften them by cutting a coil or two..  I'm sure we could get the first batch to work through trial and error pretty easily.  If 25% is too strong, maybe you or someone could calculate exactly how many coils softens the spring by what percent.


Yes, I'm getting a spring company to make to my specs.  Spring winding equipment is very specialized, and not something a typical machine shop has.

Calculating coils to remove versus percent is the easy part, that is just math - I can take that spring and remove 1 coil, then 2 coils, then 3 coils, and tell you what percent reduction you get.  The trick is knowing what our goal is.  Nice thing is that if 25% is too high, and we go about this coil by coil reduction exercise, once we know what our target is for energy absorption, I can design the ideal spring based on that result.

It would cost another $500 run to do it, but by that time we would not only have the assurance that the idea has merit, but we would also know if enough people buy this to justify.  Personally, I think it has a chance.  Enough people shoot suppressed, and without a gas block valve, that there is a need.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: ShootingSight on August 29, 2017, 08:55:05 AM
BTW, the +25% energy option would make the charging handle go from 11lb load in the forward position and 16lb load in the back position, to 13lb in the forward position and 20 lb in the back position.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: xdmikey on August 29, 2017, 09:38:36 AM
I have never had any issues while shooting suppressed but I rarely put more than 100 rounds down range. Are the issues something that surface in excess of that total? Also, my usual cleaning routine would be swabbing the barrel for nothing I get clean patches. And I rarely shoot benched; at best I throw it over my bag.

This being said, I'd be in if I'm shooting on borrowed time so to speak.

Art, you'll be leaving this post open, looking for interest, right?

Thanks Art


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: mikep7m10 on August 29, 2017, 11:47:33 AM
Would it be possible to nest a 'helper' spring?  At least as a trial to determine what weight is best.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: ShootingSight on August 29, 2017, 12:23:59 PM
Unfortunately, there isn't enough space in the diameter to fit in an additional spring, nor is there any room in the length, as the current spring has the coils go solid (or very close) in the bolt back position.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: ShootingSight on August 29, 2017, 01:11:51 PM
I have never had any issues while shooting suppressed but I rarely put more than 100 rounds down range. Are the issues something that surface in excess of that total? Also, my usual cleaning routine would be swabbing the barrel for nothing I get clean patches. And I rarely shoot benched; at best I throw it over my bag.

This being said, I'd be in if I'm shooting on borrowed time so to speak.

Art, you'll be leaving this post open, looking for interest, right?

Thanks Art

Others need to comment on this. I've only shot my Tavor suppressed with a 30 cal can on it, which I assume produces less back-pressure than a 223 can, and I did not see any issues.  My involvement in this is because others suggested there was a need, and I did the spring math and know spring suppliers.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: RabbitSlayer on August 29, 2017, 05:52:14 PM
It might take a little time to kick off once we find the correct spring ratio..
But I think in time there would be enough people wanting to buy aftermarket springs that it would be worth it.

I'm sure there are plenty of people reading this thread that don't post here waiting for the results.


Edit, eventually there would probably also be a market for the standard factory ratio spring that some might just want as an extra as well.  However I think the suppressor market is big enough that the extra power springs would dominate sales.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: ShootingSight on August 29, 2017, 06:24:13 PM
I assume that if you want a spare standard power spring, IWI would be your best source.  They buy WAY more than I do, and will be able to offer the best price.

BTW, I looked up the 300BLK kit they sell, and it comes with a new 'recoil management system', so I presume they tuned the spring to make 300BLK work.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: xdmikey on August 29, 2017, 07:36:21 PM
Art, I have both 223 & 308 cans and I can shoot a vid showing gas/smoke. Unfortunately I will have to wait for the range in houston to dry out.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: Hkbeltfed on August 30, 2017, 06:29:37 AM
I think you'll find stronger recoil springs will do little to nothing to keep the bolt closed longer or reduce gas. Search for George M. Chinn's firearms design books on the net for enlightenment.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: ShootingSight on August 30, 2017, 08:22:08 AM
I think you are 100% correct.  If reduction of gas is the only goal here, the spring is not the answer.  A reduced flow valve would be the way to do that.

However my understanding was that when suppressed, the action cycles a lot more violently and there can then be issues with reliability.  So instead of the spring absorbing part of the energy, then the shooter absorbing the rest when the bolt carrier slams into the buttstock, a stiffer spring would mean more energy goes into the spring, so the BCG is moving slower when it reaches the end of its stroke.  This reduces the recoil shock to the shooter, and gives the trigger mechanism more time to catch the hammer sear reliably.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: AZ-Chris on August 30, 2017, 11:22:09 AM
The result I hope to see is exactly what Art just described . . . slowing the speed of the bolt action cycling.  When I shoot my Tavor SAR with either my 30 cal cans (Rugged Surge & Razor) or my 5.56 GemTech Trek, I will occasionally experience a failure to eject.  The spent case just cant get out of the way fast enough and are dented/deformed by the new round being fed.

I personally don't feel the gas issues with the Tavor are any worse than with my ARs . . . that is to say, it's not pleasant, but not a show stopper.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: blottogg on August 30, 2017, 12:41:52 PM
Shooting with a Gemtech Halo, the bolt velocity is definitely faster, but I haven't noticed a bigger "thump" at the end of the bolt travel.  I've accommodated the higher velocity by removing the brass deflector to prevent brass re-ingestion, but haven't noticed any damage or additional wear in over 1000 rounds of suppressed shooting.  I have noticed a much stronger blast of gas out the ejection port when shooting cross-shoulder.  The Tavor piston design is double diameter, so the high pressure initial push acts on the small diameter front of the piston, and as pressure drops during backwards travel the second, larger diameter portion of the piston is exposed.  When suppressed, the gas pressure acting on the larger portion of the piston is higher, and counteracting that is where this spring might be useful.  At the end of the piston travel, it actually clears the cylinder, venting any remaining pressurized gas into the receiver (and your face if shooting cross-shoulder).  It's a simple (and less expensive, though messier) way of mitigating over-pressure in a non-adjustable system, and is probably why I haven't seen any damage to moving bits after all the suppressed firing, or felt the bolt slamming against the fully compressed spring.  Or maybe I just haven't been paying attention.

I like the idea of having a stiffer recoil spring available for tuning with a suppressor, but for the moment I don't see the need, at least for the combination of hardware I'm currently running on my gun.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: RabbitSlayer on August 30, 2017, 04:15:14 PM
I think you'll find stronger recoil springs will do little to nothing to keep the bolt closed longer or reduce gas. Search for George M. Chinn's firearms design books on the net for enlightenment.

Lol wut?

Stiffer recoil springs increase the time it takes for the action to cycle, stiffer recoil springs slow the cyclic rate of the bolt.  In fact, even guys who shoot suppressed handguns benefit from heavier recoil springs, because it reduces pop near the action, which means less gas is hitting the air by the breach.

Science bro.  This is well documented.




Title: Re: Stronger recoil spring for suppressed Tavor
Post by: RabbitSlayer on August 30, 2017, 04:35:26 PM
Shooting with a Gemtech Halo, the bolt velocity is definitely faster, but I haven't noticed a bigger "thump" at the end of the bolt travel.  I've accommodated the higher velocity by removing the brass deflector to prevent brass re-ingestion, but haven't noticed any damage or additional wear in over 1000 rounds of suppressed shooting.  I have noticed a much stronger blast of gas out the ejection port when shooting cross-shoulder.  The Tavor piston design is double diameter, so the high pressure initial push acts on the small diameter front of the piston, and as pressure drops during backwards travel the second, larger diameter portion of the piston is exposed.  When suppressed, the gas pressure acting on the larger portion of the piston is higher, and counteracting that is where this spring might be useful.  At the end of the piston travel, it actually clears the cylinder, venting any remaining pressurized gas into the receiver (and your face if shooting cross-shoulder).  It's a simple (and less expensive, though messier) way of mitigating over-pressure in a non-adjustable system, and is probably why I haven't seen any damage to moving bits after all the suppressed firing, or felt the bolt slamming against the fully compressed spring.  Or maybe I just haven't been paying attention.

I like the idea of having a stiffer recoil spring available for tuning with a suppressor, but for the moment I don't see the need, at least for the combination of hardware I'm currently running on my gun.

There is an angled shell deflector that deflects brass downwards maybe this would help?


Here it is..  https://www.bullpuparmory.com/product_p/pa-tavx95-shdef.htm

Anyone try this ?

It's only 12 bucks, so if it didn't work one could always take a file to it and try to get the proper angle.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: Hkbeltfed on August 30, 2017, 09:56:09 PM
Stiffer recoil springs increase the time it takes for the action to cycle, stiffer recoil springs slow the cyclic rate of the bolt.  In fact, even guys who shoot suppressed handguns benefit from heavier recoil springs, because it reduces pop near the action, which means less gas is hitting the air by the breach.

Science bro.  This is well documented.

My comments were in reference to keep the breech closed longer and reducing gas. Comparing it to handguns with barrels that recoil with the slide is irrelevant. You apparently feel you already know more than George M. Chinn which is funny all by itself considering he wrote volumes on firearms mechanisms and design. My previous comments are "well documented". That said, I'm not here to bicker with you, so carry on.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: RabbitSlayer on August 30, 2017, 10:57:44 PM
Stiffer recoil springs increase the time it takes for the action to cycle, stiffer recoil springs slow the cyclic rate of the bolt.  In fact, even guys who shoot suppressed handguns benefit from heavier recoil springs, because it reduces pop near the action, which means less gas is hitting the air by the breach.

Science bro.  This is well documented.

My comments were in reference to keep the breech closed longer and reducing gas. Comparing it to handguns with barrels that recoil with the slide is irrelevant. You apparently feel you already know more than George M. Chinn which is funny all by itself considering he wrote volumes on firearms mechanisms and design. My previous comments are "well documented". That said, I'm not here to bicker with you, so carry on.

I don't need to read volumes of books to comprehend a simple concept.  Instead of telling us to go read a book; why don't you simply explain the solution we are looking for?
If you have a better solution than adjusting recoil spring weight for our Tavors being overgassed when using suppressors, I am sure we would all love to hear it.  BTW, for those of us shooting 556 Tavors, an adjustable gas block is not an option.

Also, I have a hard time seeing how the pistol reference is irrelevant.  Both blowback operated and gas operated firearms actions timing work in direct correlation with the recoil spring weight.  Many people refer to blowback operation as a simplified form of gas operation.
The #1 suggestion people get in regards to having an overgassed firearm is to use a heavier recoil spring/buffer, so I think the most logical route for us here is to at least try a heavier recoil spring.

But by all means, if you have a better idea please ''enlighten'' us.



Title: Re: Stronger recoil spring for suppressed Tavor
Post by: blottogg on August 30, 2017, 11:43:36 PM
There is an angled shell deflector that deflects brass downwards maybe this would help?


Here it is..  https://www.bullpuparmory.com/product_p/pa-tavx95-shdef.htm

Anyone try this ?

It's only 12 bucks, so if it didn't work one could always take a file to it and try to get the proper angle.

I bought one of those (two, actually) and it didn't solve the problem for me.  Then I started grinding down the deflector (thinking I might have to do this is why I bought 2...like you said, they're not expensive) trying to change the angle of the deflector face enough to keep the brass from bouncing back in to the receiver, but that didn't solve the problem, either.  Finally just took off the deflector (and the ejection port surround that the deflector holds in), and haven't had a problem since.  Looking back, a lower back-pressure suppressor solution would have been less of a pain (OSS, or a 7.62mm can), but c'est la guerre.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: RabbitSlayer on August 31, 2017, 12:33:03 AM
There is an angled shell deflector that deflects brass downwards maybe this would help?


Here it is..  https://www.bullpuparmory.com/product_p/pa-tavx95-shdef.htm

Anyone try this ?

It's only 12 bucks, so if it didn't work one could always take a file to it and try to get the proper angle.

I bought one of those (two, actually) and it didn't solve the problem for me.  Then I started grinding down the deflector (thinking I might have to do this is why I bought 2...like you said, they're not expensive) trying to change the angle of the deflector face enough to keep the brass from bouncing back in to the receiver, but that didn't solve the problem, either.  Finally just took off the deflector (and the ejection port surround that the deflector holds in), and haven't had a problem since.  Looking back, a lower back-pressure suppressor solution would have been less of a pain (OSS, or a 7.62mm can), but c'est la guerre.

Interesting. Thanks for the feedback.
I'm trying to design a can with .27" baffles that also has reduced back pressure.  I'm thinking maybe an otb design with ports in the blast baffle.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: Hkbeltfed on August 31, 2017, 06:33:04 AM
I don't need to read volumes of books to comprehend a simple concept.  Instead of telling us to go read a book; why don't you simply explain the solution we are looking for?
If you have a better solution than adjusting recoil spring weight for our Tavors being overgassed when using suppressors, I am sure we would all love to hear it.  BTW, for those of us shooting 556 Tavors, an adjustable gas block is not an option.

Also, I have a hard time seeing how the pistol reference is irrelevant.  Both blowback operated and gas operated firearms actions timing work in direct correlation with the recoil spring weight.  Many people refer to blowback operation as a simplified form of gas operation.
The #1 suggestion people get in regards to having an overgassed firearm is to use a heavier recoil spring/buffer, so I think the most logical route for us here is to at least try a heavier recoil spring.

But by all means, if you have a better idea please ''enlighten'' us.

I get it, you're a know-it-all and you don't read. That's why this is a waste of time. I'm not suggesting you read volumes. I'm suggesting you refer to facts from an engineer who wrote volumes on firearms mechanisms including all of the science, formulas, and math behind it.

First you're comparing the Tavor to a handgun with a browning action where the barrel recoils with the slide and now you're referring to it as blowback which is incorrect and another type of action. Again, if you don't know the difference between locked breech, a Browning type, and blowback, look it up. That said, if you think blowback is relevant... http://www.orions-hammer.com/blowback/

An excerpt re: blowback: "NOTE: There is one point which requires special clarification at this time.  In many descriptions of blowback actions, it is strongly implied that the driving spring contributes a substantial portion of the resistance which limits acceleration imparted to the bolt by the powder gases.  Actually, this is not so.  Although it is true that the driving spring absorbs the kinetic energy of the recoiling bolt and thus limits the total distance it moves, the resistance of the spring does not have any real effect in the early phase of the cycle of operation.  The bolt acceleration occurs mainly while the powder gas pressures are high and are exerting a force of many thousands of pounds on the bolt.  The driving spring, in order to permit the bolt to open enough to allow feeding, must offer a relatively low resistance.  Although this resistance is sufficient to absorb the bolt energy over the comparatively great distance through which the bolt moves in recoil, it is not great enough to offer significant opposition to the powder gas pressure until the chamber pressure has dropped to a relatively low level well after the projectile has left the muzzle."

The solution you're looking for is an adjustable gas mechanism. The fact that you feel it's not an option is more ignorance in line with you narrow minded, know-it-all thinking in your posts above. Beyond that, its to vent excess gas in a controlled (desirable) fashion.

BTW, why are simple posts, like my first one, constantly met with snarky responses from you, like all of yours?

Edited to add: apologies to Shooting Sight. I realize the intention of the thread is to reduce the violence of suppressed recoil and appreciate it. Sorry for the derail.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: RabbitSlayer on August 31, 2017, 03:30:43 PM
I don't need to read volumes of books to comprehend a simple concept.  Instead of telling us to go read a book; why don't you simply explain the solution we are looking for?
If you have a better solution than adjusting recoil spring weight for our Tavors being overgassed when using suppressors, I am sure we would all love to hear it.  BTW, for those of us shooting 556 Tavors, an adjustable gas block is not an option.

Also, I have a hard time seeing how the pistol reference is irrelevant.  Both blowback operated and gas operated firearms actions timing work in direct correlation with the recoil spring weight.  Many people refer to blowback operation as a simplified form of gas operation.
The #1 suggestion people get in regards to having an overgassed firearm is to use a heavier recoil spring/buffer, so I think the most logical route for us here is to at least try a heavier recoil spring.

But by all means, if you have a better idea please ''enlighten'' us.

I get it, you're a know-it-all and you don't read. That's why this is a waste of time. I'm not suggesting you read volumes. I'm suggesting you refer to facts from an engineer who wrote volumes on firearms mechanisms including all of the science, formulas, and math behind it.

First you're comparing the Tavor to a handgun with a browning action where the barrel recoils with the slide and now you're referring to it as blowback which is incorrect and another type of action. Again, if you don't know the difference between locked breech, a Browning type, and blowback, look it up. That said, if you think blowback is relevant... http://www.orions-hammer.com/blowback/

An excerpt re: blowback: "NOTE: There is one point which requires special clarification at this time.  In many descriptions of blowback actions, it is strongly implied that the driving spring contributes a substantial portion of the resistance which limits acceleration imparted to the bolt by the powder gases.  Actually, this is not so.  Although it is true that the driving spring absorbs the kinetic energy of the recoiling bolt and thus limits the total distance it moves, the resistance of the spring does not have any real effect in the early phase of the cycle of operation.  The bolt acceleration occurs mainly while the powder gas pressures are high and are exerting a force of many thousands of pounds on the bolt.  The driving spring, in order to permit the bolt to open enough to allow feeding, must offer a relatively low resistance.  Although this resistance is sufficient to absorb the bolt energy over the comparatively great distance through which the bolt moves in recoil, it is not great enough to offer significant opposition to the powder gas pressure until the chamber pressure has dropped to a relatively low level well after the projectile has left the muzzle."

The solution you're looking for is an adjustable gas mechanism. The fact that you feel it's not an option is more ignorance in line with you narrow minded, know-it-all thinking in your posts above. Beyond that, its to vent excess gas in a controlled (desirable) fashion.

BTW, why are simple posts, like my first one, constantly met with snarky responses from you, like all of yours?

Edited to add: apologies to Shooting Sight. I realize the intention of the thread is to reduce the violence of suppressed recoil and appreciate it. Sorry for the derail.

God I hate pseudo intellectuals.


Edit: Thread derailed, want this to get back on topic.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: RabbitSlayer on August 31, 2017, 06:33:06 PM

The solution you're looking for is an adjustable gas mechanism. The fact that you feel it's not an option is more ignorance in line with you narrow minded, know-it-all thinking in your posts above. Beyond that, its to vent excess gas in a controlled (desirable) fashion.

BTW, why are simple posts, like my first one, constantly met with snarky responses from you, like all of yours?

This thread is about a heavier recoil spring, not an adjustable gas block.  Do you know where to buy an adjustable gas block for the 556 Tavor?  Are you going to fund the research and development to build an adjustable gas block for the 556 Tavor?
The answer to both of those questions is no, so f-ck off.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: Hkbeltfed on August 31, 2017, 08:11:41 PM
If I have ruined this thread, then I'm sorry. That said, you have gone off the deep end. I guess your questions will remain unanswered. You can take solace in the following...

I think you are 100% correct.  If reduction of gas is the only goal here, the spring is not the answer.  A reduced flow valve would be the way to do that.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: 45r on September 02, 2017, 11:55:07 PM
Tuning the gas will give better results than anything done with springs.
Hope you can make it work but nobody has yet.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: ShootingSight on September 08, 2017, 08:35:34 AM
So I put this at 3 people interested, and 2 possibles...

This spring will slow the action and the thump of the BCG hitting the hard stop at the end of the travel.  However the piston vents the gas in the first 10% of its stroke, so it will do little to reduce the amount of gas that is vented into the gun/face.

So is it still worth it?  Seems like people are shooting without it, and report few problems with the recoil - most issues are with the gas.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: AZ-Chris on September 08, 2017, 10:06:09 AM
I'm still interested.  Slowing the bolt down will fix the minor reliability issues I've experienced (occasional failure to eject and the brass gets beat up pretty bad).  Gas in the face, while somewhat annoying, isn't a reliability problem.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: SteveG75 on September 08, 2017, 09:50:09 PM
I am interested as well.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: ShootingSight on September 15, 2017, 01:06:54 AM
OK, I pulled the trigger and placed an order.  We'll know in several weeks.

If you want in for $50 for 2 springs, email me at art@shootingsight.com.  There are no guarantees.  I guessed at the 25% more power.  Good thing is with a Dremel and a cutoff wheel, you can remove loops one at a time, and since you are getting 2 springs, you can't go too far.

I ran the math, and while we are starting at a spring that absorbs 25% more energy through the stroke, you reduce that almost exactly 1% per loop you cut off, so you cut off 3 loops, you now only absorb 22% more energy through the stroke.

Once these work, I'll put them up for $35 each, so I'll let you struggle with the decision if you want in early at a reduced price per spring, but a slightly higher overall.

There has been confirmation in this thread that these will work for either the Tavor or the X-95.  Of course you can bet we will repeat this product for the .308 Tavor when it comes out.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: AZ-Chris on September 15, 2017, 12:19:40 PM
OK, I pulled the trigger and placed an order.  We'll know in several weeks.

If you want in for $50 for 2 springs, email me at art@shootingsight.com.  There are no guarantees.  I guessed at the 25% more power.  Good thing is with a Dremel and a cutoff wheel, you can remove loops one at a time, and since you are getting 2 springs, you can't go too far.

I ran the math, and while we are starting at a spring that absorbs 25% more energy through the stroke, you reduce that almost exactly 1% per loop you cut off, so you cut off 3 loops, you now only absorb 22% more energy through the stroke.

Once these work, I'll put them up for $35 each, so I'll let you struggle with the decision if you want in early at a reduced price per spring, but a slightly higher overall.

There has been confirmation in this thread that these will work for either the Tavor or the X-95.  Of course you can bet we will repeat this product for the .308 Tavor when it comes out.

email sent.  I'm in for $50 and 2 springs.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: RabbitSlayer on September 16, 2017, 01:36:01 AM
In


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: ShootingSight on September 16, 2017, 07:56:49 PM
OK, I put up a product on my web site.  I made it 3 springs for $50 to sweeten it.  If we find a benefit we like, they will be $30 each after we conclude R&D, so getting in early is about half the cost per spring.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: pilot4prophet on September 17, 2017, 07:10:42 AM
Shooting Sight,  Unable to add the item to the cart. Says out of stock.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: chowser51 on September 17, 2017, 07:26:36 AM
ditto. can't add to cart.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: ShootingSight on September 17, 2017, 09:54:39 AM
OK, fixed it.  I put it as out of stock, but to allow backorders.  Frankly, I'm not impressed with the shopping cart software GoDaddy provides.

So now it is in stock.  Thanks for letting me know.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: AZ-Chris on September 17, 2017, 04:37:26 PM
I just placed my order.  Thanks again Art for taking on this project!


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: ShootingSight on September 28, 2017, 03:22:33 PM
Wow, that was fast!  New springs are in!

A few people got in on the 3 for $50 deal up front, so their springs are out in the mail.  I'll leave the deal up for the next few days in case someone wants in soon.  They will go up to $30 each this weekend.

I just opened the box, have not even installed one in my Tavor yet, let alone shot it, so I have no results to report, but was just excited and wanted to let people know.

Art


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: ShootingSight on September 28, 2017, 09:19:52 PM
Someone just asked what harm could come from this, especially firing unsuppressed, so I figured: let's brainstorm everything we think could go wrong.

Spring has 25% more energy in it, so when the bolt closes, it will close faster.  I can't imagine that would hurt the rifle.  The two things I can think of are:

1.  If you have a misfeed, it will really jam the round in there. 
2.  The other thing is that the firing pin spring has to hold the pin back against a harder closing, so there could be a risk of a slam fire.  I'd test these with only 1 or 2 in the mag the first time.

Also, the obvious failure is the inability to cycle the gun unsuppressed.

The gun will cycle slower, but that should be a plus for trigger reliability.

Anything else?

Art


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: RabbitSlayer on September 28, 2017, 10:29:27 PM
I believe cycling your action ( pulling your charging handle back and letting it slam forward ) with no ammo in the gun is probably harsher than the gun cycling with the 25% spring with it stripping ammo out of the mag.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: ShootingSight on September 29, 2017, 01:31:40 PM
Wonder how much energy it takes to strip a round.

I have never heard of issues from dry cycling with a normal spring.  So is cycling with a +25% spring and ammo better or worse than a normal spring without ammo?

On a related - I just bought a high speed camera, so when I test this spring, I'll film it, and we can see how the cycling is different in speed and in stroke length.  Ohhhhh! That will be cool.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: RabbitSlayer on September 30, 2017, 01:32:07 AM
Dry cycling should be no problem at all.

Can't answer the other questions, but I highly doubt the 25% spring would cause any damage.  The Tavor is build out of the same type of materials that 308 semi autos are built out of, those have harsher springs and whatnot so I doubt there will be issues.

Bolt guns are made out of softer metals and shoot calibers like 300 mag...

I doubt the spring would hurt the gun in any way.  But, it could cause cycling issues till we figure out the propper +% ratio.
In the end it should all be worth it.


That is awesome you have a high speed camera, I seriously cannot wait to see that footage !


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: ShootingSight on September 30, 2017, 08:55:46 AM
Next question is where the sweet spot is.  I see two possibilities.

If you get the spring such that it just barely cycles with a suppressor, that is ideal for the suppressed mode, but then it will not cycle unsuppressed.

Question is if the OEM spring still lets the BCG smack back full-stroke with energy to spare when firing unsuppressed, you could boost the spring power till unsuppressed just barely cycles (with a margin to assure reliability).  That would mean suppressed is not as tame as it could be, but at least you found a common window, so the spring cycles in both modes.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: pilot4prophet on October 03, 2017, 06:34:32 AM
Got my springs today, Thanks Art!


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: AZ-Chris on October 03, 2017, 07:35:57 PM
Mine arrived too.  Thanks Art!


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: ShootingSight on October 03, 2017, 08:31:18 PM
Don't forget to post results.  I don't know when I'll get out to test, but I only have a 30 cal can, which likely will not give the back pressure that a true 223 can will.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: AZ-Chris on October 03, 2017, 10:32:50 PM
I just installed the new stiffer spring.  I hope to get out to the range tomorrow with my GemTech Trek 5.56 can.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: AZ-Chris on October 05, 2017, 01:54:22 PM
I just got back from the range, having only run 3, 30-round magazines of XM193.  The first 30 rounds were fired un-supressed with ZERO malfunctions.  I could not really tell the difference in the bolt cyclic rate and the brass ejected in the 3 o'clock direction.  The recoil impulse seemed a bit stronger than with the stock spring.

The next two magazines were spent using my GemTech Trek 5.56, thread-on suppressor.  Again, there were ZERO malfunctions.  The bolt cyclic rate was clearly slower than when using the stock spring, but it's still faster than I would prefer.  The brass was ejecting between 1 and 2 o'clock (with most cases going forward of the firing line and therefore irretrievable).  Of the cases I was able to recover, most had a visible dent in case about 2/3 the way up from the base.

I measured the pull weight of the charging handle with the new, stiffer spring (using a portable luggage scale) and found it to be between 25 & 30 lbs to lock the bolt back.  I didn't think to measure this with the stock spring.

So far, I think the new, stronger spring is a definite improvement over the stock spring, though I think an even stronger spring may be better.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: RabbitSlayer on October 05, 2017, 04:38:01 PM
I just got back from the range, having only run 3, 30-round magazines of XM193.  The first 30 rounds were fired un-supressed with ZERO malfunctions.  I could not really tell the difference in the bolt cyclic rate and the brass ejected in the 3 o'clock direction.  The recoil impulse seemed a bit stronger than with the stock spring.

The next two magazines were spent using my GemTech Trek 5.56, thread-on suppressor.  Again, there were ZERO malfunctions.  The bolt cyclic rate was clearly slower than when using the stock spring, but it's still faster than I would prefer.  The brass was ejecting between 1 and 2 o'clock (with most cases going forward of the firing line and therefore irretrievable).  Of the cases I was able to recover, most had a visible dent in case about 2/3 the way up from the base.

I measured the pull weight of the charging handle with the new, stiffer spring (using a portable luggage scale) and found it to be between 25 & 30 lbs to lock the bolt back.  I didn't think to measure this with the stock spring.

So far, I think the new, stronger spring is a definite improvement over the stock spring, though I think an even stronger spring may be better.


Thank you for the report.  I don't think the ejection pattern is as indictive to proper gas pressure as with a DI AR, I think the piston system of the Tavor probably has a different ideal ejection pattern.  However judging by your description, it does sound like the can is causing some over pressure for you, or at least more noticable pressure increase.
FWIW my stock x95 gives brass the same dents.
Just curious did you notice any less blowback with the stiffer spring by chance?  My stock gun can get pretty gassy once I start rapid firing, most of the gas leaks out of the rear of the optic rail/gas tube.
Did the new spring fit pretty easy?


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: ShootingSight on October 05, 2017, 06:12:34 PM
Wow, Chris, thanks for the excellent report.

I find it interesting that 25% more energy still cycles unsuppressed fine.  I wonder how much higher we can go, or if we should just run with it and say 25% extra is an improvement.

I am delighted that there is a window which improves suppressed fire, and still allows unsuppressed fire.  Makes me think the design goal ought to be to find the strongest spring that will still cycle unsuppressed.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: AZ-Chris on October 05, 2017, 06:16:39 PM
Spring replacement is quite easy and took all of 10-minutes, though you do have to push harder to compress the spring getting the retaining collar on.

The brass ejection pattern is different for me when shooting suppressed.  I've never had the brass shoot forward that much before . . . in fact I've had multiple complaints from people to my right that spent brass nails them pretty good (at my outdoor range).  With the new spring, the brass is traveling a good 6-10 feet forward.  The gun is just as gassy with the new spring, especially when shooting rapidly, so I say there's no improvement on that.  (I also get most of the gas coming from the rear of the rail).

Also, unsupressed, the brass cases do not get dented.



Title: Re: Stronger recoil spring for suppressed Tavor
Post by: AZ-Chris on October 05, 2017, 06:25:23 PM
Wow, Chris, thanks for the excellent report.

I find it interesting that 25% more energy still cycles unsuppressed fine.  I wonder how much higher we can go, or if we should just run with it and say 25% extra is an improvement.

I am delighted that there is a window which improves suppressed fire, and still allows unsuppressed fire.  Makes me think the design goal ought to be to find the strongest spring that will still cycle unsuppressed.

Hi Art, the new spring is a definite improvement as far as I can tell, but I do want to shoot it more as well as try out my Rugged Razor, 30-cal can.

Given your earlier comments about the spring, I was delighted when I experienced no trouble shooting unsupressed.  The recoil impulse did feel a bit sharper, and I wasn't paying attention to muzzle rise. 

Overall, I think a stronger spring would be even better, but I'm happy with the new spring.  Thanks for making that happen!


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: AZ-Chris on October 06, 2017, 06:54:55 PM
Just got home from my 2nd range session, this time using my Rugged Razor, 30-cal suppressor and 3, 30-round magazines of XM193.

The first 30 rounds were fired unsuppressed and again, I had zero malfunctions . . . flawless operation.  Shells ejected at the usual 3 o'clock position and I saw no damage to the brass cases.  Muzzle rise might have been a little more pronounced, but not by much and since I was going to use the Rugged Razor, I needed to use the Rugged flash hider muzzle device in lieu of usual compensator.

I then proceeded to fire another 2 magazines suppressed.  The shells ejected between 2 and 3 o'clock and not quite as forcefully as when I used my GemTech Trek.  The cases were still a bit dented in the same place as yesterday (about 2/3 the way up from the base).

I can say, without a doubt, that the new, stronger recoil spring is an improvement over stock when shooting suppressed (bolt speeds are noticeably slower and less violent) and makes little to no difference when shooting unsuppressed.  I did NOT notice any significant impact on gassyness . . . it is what it is.

I'd be interested in trying a still stronger recoil spring if there is further interest, but I'm very glad I have this new spring because it does adequately address my biggest concern about shooting the Tavor suppressed.



Title: Re: Stronger recoil spring for suppressed Tavor
Post by: ShootingSight on October 10, 2017, 09:23:53 AM
Chris, some clarification please:

When you say the brass is not dented when firing unsuppressed with the new spring ...... is the brass dented when unsuppressed with the old spring?

If the spring does nothing more than get rid of denting when unsuppressed, that's a benefit even if you do not own a can.

Art


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: AZ-Chris on October 10, 2017, 09:27:55 AM
I've not experienced dented cases when shooting unsuppressed with either spring.  The only time I see the cases dented is when the suppressor is on.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: SteveG75 on October 14, 2017, 07:49:02 PM
Got my spring from Art today. Swapped it and headed to the range. Functioned great both unsuppressed and when using my Rugged Razor can.  Also, my Tavor really likes Federal 69 grain Match King.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: AZ-Chris on October 25, 2017, 06:31:27 PM
How come we only have 2 reports from people that got the stronger recoil spring?  I'd like to hear about the results from everyone that got them. 

Personally, I'd sign up for an even stronger spring, but I'm sure Art would want to hear from everyone else before trying something different.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: chowser51 on October 26, 2017, 10:47:08 AM
I got my spings in but haven't had a day off work to get to it.  I took next week off but I will be in Fort Bragg.  Once I return, I will have a few days off before work so I will swap a spring out and try it.  The suppressor I will be using is a .30 cal AAC762SDN6.
I do not recall if cases were dented before because I picked my X95 to be the one that shoots up all the steel cased ammo I was given so I never bothered to collect any.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: ShootingSight on November 03, 2017, 02:32:25 PM
Got to the range with a high speed camera.  I shot OEM spring unsuppressed, as well as suppressed.  And I shot the +25% spring both unsuppressed and suppressed.

What I measured was how much time elapsed from when the bolt carrier first started to move, until the leading edge of the bolt carrier passed out of view of the port.

OEM spring unsuppressed, ie a 'normal' setup, took 15ms.
Moving to the +25% spring slowed the BCG by about 7% to 16ms.  Still plenty fast to cycle the gun.

Suppressed, with a SureFire 30 cal suppressor caused the OEM spring to cycle at 13ms.
Suppressed the +25% spring cycled at 15ms.

Net, the +25% spring makes a suppressed rifle cycle at about the same speed as an unsuppressed OEM spring, so in that regard, the guess of +25% was right on.  Testing also confirmed that shooting the +25% spring unsuppressed did not cause an unacceptable slowing of the BCG.

Question still remains if we could have gone even higher, perhaps to a +50%, but that will be for a future test.

Here is the link to the video I shot. https://www.youtube.com/watch?v=IspNC27nPGQ&feature=youtu.be (https://www.youtube.com/watch?v=IspNC27nPGQ&feature=youtu.be)


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: AZ-Chris on November 03, 2017, 05:45:42 PM
Wow, that was really cool to watch.  Nice job Art!

I'm still a bit surprised that the suppressed gun with the stronger spring operates at the same cyclic rate as the unsuppressed OEM spring as it does not jive with my perception (nor dented brass cases).

The video doesn't lie, you nailed it Art.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: ShootingSight on November 03, 2017, 07:14:49 PM
I actually did motion analysis.  The data was messy, as measuring exact pixels was not clear, however my takeaway was that BCG velocity was high throughout the recoil, and it hit the back of the receiver without having slowed a whole lot.  Ie the plots of velocity were not dropping a whole lot as the BCG got to the end of its stroke.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: SteveG75 on November 03, 2017, 07:51:03 PM
Art's results make sense with my qualitative observation. With the +25% spring, shooting suppressed was ending up where it would shooting unsuppressed with the stock spring.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: AZ-Chris on November 24, 2017, 11:43:57 PM
I am a bit disappointed as it seems this project has come to an end. 

I would have liked to try an even stronger spring with the ability to remove coils in order to "tune" an appropriate strength to suit my needs.  While the 25% stronger spring is a definite improvement, my dented brass cases indicate more could be done along these lines.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: ShootingSight on November 25, 2017, 09:46:13 AM
Might have fared better if I had titled the thread for the X-95 instead of the Tavor .... I assumed most people recognized that they were interchangeable in this case.

With the Tavor being phased out, I guess it didn't raise any enthusiasm.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: TNC on November 25, 2017, 12:50:48 PM
I am a bit disappointed as it seems this project has come to an end. 

I would have liked to try an even stronger spring with the ability to remove coils in order to "tune" an appropriate strength to suit my needs.  While the 25% stronger spring is a definite improvement, my dented brass cases indicate more could be done along these lines.

AZ, on the dented brass, I guess you're talking about the "D" dent in the case mouth?  If so, I don't think there's much to be done about that as I think that's a byproduct of the ejector/extractor design and the deflector.  My hottest ammo, Federal Eagle XM193, chronos around 3300fps out of a 20" AR.  My slowest ammo, PMC .223 (not PMC MTAC),  chronos at about 3050 in the same AR test mule.  The "D" dent occurs in both rounds equally.  Even my accuracy loads with 68g and 77g HPBT's get the small dent.

I don't know...I get the impression it's just the nature of the design...at least it's consistent in my Tavor.  This is shooting non-suppressed.  And as far as the mouth dent, it has no bearing on really damaging the brass.  The resizing process removes that, and the brass is going to die from repeated loadings at other locations well before the case mouth can cause problems.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: JimD9 on November 25, 2017, 02:18:06 PM
Also disappointed this came to an end, was wanting to try one out myself.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: TNC on November 25, 2017, 08:45:14 PM
Also disappointed this came to an end, was wanting to try one out myself.

Are you talking about the "springs" coming to an end?  Aren't they available on Art's site right now?  I was on his site yesterday and could swear I saw them.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: AZ-Chris on November 26, 2017, 12:07:05 PM
My dented brass occurs about half-way up the length of the brass case . . . not the mouth.
(https://s26.postimg.org/m1ba67ng5/IMG_0456.jpg) (https://postimg.org/image/m1ba67ng5/)


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: TNC on November 26, 2017, 05:19:01 PM
AZ, that's different.  I can't get mine to do anything but the case mouth "D" regardless of the power or lack thereof of the ammo.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: ShootingSight on November 28, 2017, 09:31:39 AM
The +25% springs are still available - that part has not come to an end.  However, given the relatively high price of a spring run, and the relatively few that have sold (maybe a dozen), my interest in investing in another spring run to explore higher force yet is limited.  So he meant the development is at a stall.

With time, if interest picks up, things might change, but I think the number of people who shoot suppressed, and feel a need here, is low.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: AZ-Chris on November 28, 2017, 01:48:33 PM
well said Art.

If you decide to make a stronger spring available, please let me know as I will surely put my money where my mouth is.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: SteveG75 on December 01, 2017, 06:44:10 PM
I have been happy with the +25% spring. So, just ordered a spare for my stash. Now, if Art could just come up with something that would help with the gas out the rail when shooting suppressed.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: SteveD on December 01, 2017, 07:56:22 PM
I have been happy with the +25% spring. So, just ordered a spare for my stash. Now, if Art could just come up with something that would help with the gas out the rail when shooting suppressed.

My suppressor is in jail but I used RTV high temp silicone to help "glue down" the rail for future suppressor use. I also did it to the flismy plastic ejection port instead of buying a gasketed port cover. And since the silicone was bright red against my camo paint job, I repainted the areas and also sprayed clear enamel finish as well. Hope that seals up the rail a good bit.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: AZ-Chris on January 12, 2018, 10:51:11 PM
I experienced my first malfunction when shooting suppressed (using the stronger recoil spring and my GemTech Trek 5.56 can).  The malfunction was a stovepipe that prevented (mangled) the next round being fed into the chamber.  The stoppage could not be cleared by simply running the charging handle a few times . . . I had to drop the magazine, lock the bolt back, and reach inside to un-jam the spent case and badly bent new round.  Glad this was at the range.

Spent cases are still be rapidly/forcefully ejected in the 1 o'clock direction, making retrieval difficult.  Of the spent cases that were recovered, the usual denting in the cases shown in an earlier post were clearly evident.

While the replacement spring Art provided is a positive step in the right direction, I cannot rely on running my Tavor suppressed as a home defense option.  I require an even stronger recoil spring before I can rely on my Tavor to serve in the roll I intended it for.



Title: Re: Stronger recoil spring for suppressed Tavor
Post by: SteveD on January 12, 2018, 11:01:19 PM
You could always try modifying the brass deflector or removing it completely. It sucks to have to do anything to make it function, but we can't do anything about it :\. I was just at the range today with the extra power spring and my brass was ejecting 4:00 to 4:30. Hopefully my jailed can can work with that later.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: AZ-Chris on January 12, 2018, 11:43:47 PM
I don't think the shell deflector had anything to do with the stovepipe . . .

The problem remains . . . the cyclic rate is just too fast when shooting suppressed.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: SteveD on January 13, 2018, 12:06:35 AM
I was under the impression some stove pipes caused by suppressed use was the cyclic rate is too high and violent with the gas, ejecting the casing so violently that it bounces off the shell deflector back into the weapon. If the problem is high cyclic rate (which I have no doubt it is with suppressed Tavors), the casing hitting the deflector is something that should be considered. Some users on the forum had stovepipes but upon removing their brass deflector, making it AUG-like, seemed to solve that problem.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: AZ-Chris on January 13, 2018, 12:28:43 AM
Perhaps I need to try removing the deflector, but I'm skeptical of this theory.

I will give this a try and report back.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: SteveG75 on January 13, 2018, 12:33:19 AM
I had the same problem with stovepipes with the stock recoil spring and the stock deflector. Removing the frame solved the problem in back to back testing. I then tried the angled Percival shell deflector and have not had a problem with that either so I have kept that installed.

My limited testing also leans to using a suppressor that creates less back pressure. My go to can for the Tavor is my Rugged Razor with 7.62 end cap. Couple of decibels more than my Rugged Surge but less gas.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: AZ-Chris on January 13, 2018, 05:04:12 PM
Just got back from the range -- shooting with and without the shell deflector as the only variable.  The Tavor has the stronger recoil spring and I'm using a GemTech Trek 5.56 thread-on suppressor.

With the deflector in-place, cases eject consistently at 1 o'clock and clearly show dented cases.  I experienced another stove pipe, though it was fairly easily cleared.

Without the deflector, cases eject at 3 o'clock (nearly all cases are retrievable) but NO denting (though some scratches) on spent cases.  Unfortunately, I did experience another stove pipe, though it was easily cleared.

I think I will try out the Percival Armaments Angled Shell Deflector to see if it helps, but the real problem here is the overly gassed system and high bolt speed.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: SteveD on January 13, 2018, 07:30:56 PM
That's unfortunate. I would go to the extremes of even drilling a small hole in the gas block...but that's just me hehe. Sucks to even have to consider such great lengths. I've seen them suppressed; I guess they drilled your gas port a tad bit too big on your rifle.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: AZ-Chris on February 03, 2018, 08:39:46 PM
I just got back from a miserable range session (as if that were possible) with the Tavor.  I shot the Tavor suppressed using the GemTech Trek 5.56 can, the stronger recoil spring and new to this session, the Percival shell deflector.

I only fired 30 rounds before calling it quits . . . I was unable to fire a string longer that 3 rounds without experiencing a difficult to clear stove pipe/jam.  The Percival shell deflector is designed for light loads, definitely not for an overgassed Tavor.

(https://s26.postimg.org/5ck3d7sj9/20180203-0001.jpg) (https://postimg.org/image/5ck3d7sj9/)

I'm calling it quits with regard to using the GemTech Trek on my Tavor.  Just too many issues to resolve in order to get the gun to run reliably.  I will now focus my attention to running the Tavor with my Rugged Razor 30-cal suppressor to see if I can get more reliable operation.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: chowser51 on February 04, 2018, 02:15:21 AM
I gave up on my Specwar 556 and only rarely shoot my X95 with my .30cal can (AAC 762SDN6). Both ran fine. I just quit shooting it suppressed because of the gas in face. Less gas with the .30cal can but I canít make it through a 20 round magazine. I will get around to installing my spring and drilling a hole in the gas block when I find time.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: lee1000 on February 04, 2018, 03:05:17 AM
I gave up on my Specwar 556 and only rarely shoot my X95 with my .30cal can (AAC 762SDN6). Both ran fine. I just quit shooting it suppressed because of the gas in face. Less gas with the .30cal can but I canít make it through a 20 round magazine. I will get around to installing my spring and drilling a hole in the gas block when I find time.

I'm surprised no one is offering the gas block drilling modification as a service. I'm not a Tavor or suppressor owner yet but I'm looking. I might end up with a Sig suppressor because of the bigger diameter.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: ShootingSight on February 04, 2018, 10:45:21 AM
I test fire all the Tavor triggers, so I sometimes have range sessions that last a few hundred rounds, and occasionally get into sessions where I misfeed or stovepipe every 5 or 6.  What works for me is a good chamber scrubbing and running it wet.  I think there is just too much soot buildup that makes things not slide easily.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: SteveD on February 04, 2018, 09:14:55 PM
Reading through the problems some Tavor owners have, has anyone considered drilling a hole in the gas system to bleed off gas? Somewhere closer to the port, not near where the piston head rests (Think ShootingSight did that to just alleviate TavorFace, not the backpressure). Using this picture, maybe drill it halfway down the small tube? Will that help or completely mess up the gas system?

http://i.imgur.com/wttFk64.jpg


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: ShootingSight on February 05, 2018, 02:16:05 AM
I never did that.  Maybe Gear Head Works?  I know he experimented a lot to get his first prototype 300BLK to cycle correctly.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: SteveD on February 05, 2018, 04:49:56 AM
Ah yes, it was GearHeadWorks. I knew it was one of you aftermarket guys (Got your Extra power spring;hope that's all I need). I'm thinking if I have problems with my Tavor once my can is out of jail, I'll be the guinea pig on that experiment. Question is; where should the hole be? If the hole is too far away, closer to the piston head, the system may be overgassed still (I'm probably going to drill the smallest hole, whatever that diameter is). However, Maybe I can drill the hole bigger and it would help. If I drill too close to the gas port and it bleeds too much gas, I'm just out of luck period...

Anyone have a very educated guess on where I might drill the hole if I need to?


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: ShootingSight on February 05, 2018, 09:32:50 AM
Or even drilling behind the piston, so it does not bleed off any before the piston starts moving, but rather just starts an early exhaust.

As you pointed out, too little is inconvenient.  Too much is game over.  We got lots of taking off tools, but not so many putting back on ones.  Unless you start by drilling it to accept a screw-in gas port from maybe a SCAR, or possibly a jet from an old carburettor, or even find a size of set screw that you can start drilling out.  It would be good to just know the size and location of the hole you want, but if you are the first guy to try it, that'd be like winning the lottery.  Instead go in with the idea of making it adjustable.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: SteveD on February 05, 2018, 05:51:24 PM
I would love to make it adjustable, but I lack the confidence to drill and tap without messing up. I was looking into changing the piston somehow, but someone has already tried with no luck. Then, KNS Precision at shotshow will have a product for the AK with an adjustable gas piston...I'd much rather mess with the piston somehow.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: lee1000 on February 06, 2018, 05:18:31 AM
Or even drilling behind the piston, so it does not bleed off any before the piston starts moving, but rather just starts an early exhaust.

As you pointed out, too little is inconvenient.  Too much is game over.  We got lots of taking off tools, but not so many putting back on ones.  Unless you start by drilling it to accept a screw-in gas port from maybe a SCAR, or possibly a jet from an old carburettor, or even find a size of set screw that you can start drilling out.  It would be good to just know the size and location of the hole you want, but if you are the first guy to try it, that'd be like winning the lottery.  Instead go in with the idea of making it adjustable.

The author of the thread below reportedly did well with an adjustable gas block. It seems replacing the piston and drilling the gas tube didn't work well.

https://bullpupforum.com/index.php?topic=10875.0 (https://bullpupforum.com/index.php?topic=10875.0)


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: SteveD on February 06, 2018, 05:59:35 AM
Yeah I saw it a while back and I thought it was great. I just don't have the confidence to drill n tap, especially such hard steel. He also 3d printed his parts, which I don't have access to (maybe it's easy, though). The AK Gas piston is different because I believe there is a hole down the middle of the piston head, and it extends a bit before letting it bleed out the sides. Too bad an AK carrier has a lot of real estate where the Tavor has what 3/4" on the piston head before it runs into the spring assembly.

I would try the adjustable gas block if I could. it just seems like drilling a small hole, somewhere gas tube (not the gas cylinder!) could help and would be easier. Where the gas tube turns very thin and then turns into a larger chunk of metal is where I'd try. GearHeadWorks drilled a small hole a bit past that, more towards the piston head, to vent  excess gas, not so much affect the gas system. My hole would be 1/2-3/4" more towards the gas port/muzzle end.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: imadude on February 12, 2018, 09:27:28 PM
Is there a good way to remove the return spring?  I've watched https://www.youtube.com/watch?v=XorSllQgDEI (https://www.youtube.com/watch?v=XorSllQgDEI) on yt but when I push down against the dowel rod, there's nothing happening to loosen spring tension.  The little crossbar piece seems firmly entrenched.  This is on a x95 and my return spring is captured (butt side).


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: ShootingSight on February 12, 2018, 10:17:01 PM
You have to put in the penny, or better yet, a dime, or a washer.

What they don't say in the video is that the penny (try a dime) has to be thin enough that it blocks the spring, but not the central rod.  So it has to be thin, and it has to be seated all the way up or all the way down in the slot.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: imadude on February 12, 2018, 11:22:12 PM
You have to put in the penny, or better yet, a dime, or a washer.

What they don't say in the video is that the penny (try a dime) has to be thin enough that it blocks the spring, but not the central rod.  So it has to be thin, and it has to be seated all the way up or all the way down in the slot.

Awesome, that made all the difference.  Thank you.


Title: Re: Stronger recoil spring for suppressed Tavor
Post by: SteveD on February 13, 2018, 04:18:22 AM
I found it useful to have a 2nd pair of hands. My girlfriend easily punched out the pin while I pushed down to relieve the tension