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| | |-+  Stronger recoil spring for suppressed Tavor
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Author Topic: Stronger recoil spring for suppressed Tavor  (Read 4784 times)
ShootingSight
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« Reply #60 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
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Art Neergaard
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AZ-Chris
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« Reply #61 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.
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SteveG75
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« Reply #62 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.
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AZ-Chris
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« Reply #63 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.
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chowser51
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« Reply #64 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.
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ShootingSight
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« Reply #65 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
« Last Edit: November 03, 2017, 02:41:35 PM by ShootingSight » Logged

Art Neergaard
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AZ-Chris
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« Reply #66 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.
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ShootingSight
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« Reply #67 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.
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Art Neergaard
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SteveG75
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« Reply #68 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.
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AZ-Chris
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« Reply #69 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.
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ShootingSight
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« Reply #70 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.
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Art Neergaard
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« Reply #71 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.
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JimD9
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« Reply #72 on: November 25, 2017, 02:18:06 PM »

Also disappointed this came to an end, was wanting to try one out myself.
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TNC
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« Reply #73 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.
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AZ-Chris
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« Reply #74 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.
« Last Edit: November 26, 2017, 03:45:52 PM by AZ-Chris » Logged
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« Reply #75 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.
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ShootingSight
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« Reply #76 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.
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Art Neergaard
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AZ-Chris
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« Reply #77 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.
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SteveG75
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« Reply #78 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.
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SteveD
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« Reply #79 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.
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