Welcome, Guest. Please login or register.
January 24, 2018, 05:33:51 AM
Home Home Help Calendar Login Register
News:

Please support BullpupForum.com sponsors!!
. . . Midwest Industries . . . BullpupArmory.com . . . Shooting Sight . . . BullpupUnlimited.com . . . Homeland Guns . . . . . . . . . . . . AB Arms . . . GallowayPrecision.com . . . K & M Arms . . . . . . Geissele Automatics
+  BULLPUP FORUM
|-+  Bullpup Rifles (Auto & Semi-Auto Centerfire)
| |-+  IWI TAVOR
| | |-+  IWI Tavor SAR & X-95
| | | |-+  Over-Torqued and wrong muzzle brake for suppressor host...Accuracy test DONE!
Pages: [1] Print
Author Topic: Over-Torqued and wrong muzzle brake for suppressor host...Accuracy test DONE!  (Read 560 times)
SteveD
Member
**
Offline Offline

Posts: 104


« on: January 11, 2018, 03:45:54 AM »

EDIT: Range Trip and Groups are in!

So in anticipation for my AAC 556SD to come in soon, hopefully (check cashed 11/20/17, BUT I am using the newer barcode system so I hope the time is lower) I installed the AAC Blackout 51T Muzzle Brake. I bought it on sale on Black Friday, but just now I read that AAC recommends the Flash Hider or Brakeout on the Tavor due to the threads and whatnot. However, I decided to

1) Press the jam nut/barrel nut against the shoulder, give it a good torque.
2) Use provided shims to guesstimate how much I need. Turns out no combo worked for me to align it 100% (but I wasn't really trying ALL the combinations...) I was either over-rotated by 5-10 degrees or under-rotated by 10-20 degrees.
3) I opted to pick under-rotated and try to torque it, like a crush washer. Well ends up it didn't torque as far as I wanted, and yup, I torqued the hell out of it because I thought it could go further but it didn't. Now it is off by 5-10 degrees, just now super torqued, like probably 70 lbs. I tried to get it off, but I guess the combo of too much elbow grease and the rocksett just got it stuck.

Yeah I can try boiling water and whatnot, but, am I still good to go? There are concerns of baffle/end cap strikes with the barrel nut but considering that I used the barrel nut as a new shoulder, it shouldn't matter, right? Also over-torque I read it can affect accuracy but I'm headed to the range tomorrow to re-zero and accuracy test.

Main concern: Baffle/end cap strike later one
2ndary: Loss of accuracy (not like I care as much...if it goes from 2moa to 3moa I'm not gonna cry (k maybe just a little))

RANGE TRIP:
Very bright, some wind but most of it is blocked by vegetation. Used a Holosun 510C. Had to up the brightness so much for the bright sun that the dot was the size of the target. I was very satisfied with the accuracy and how the POI changed between different ammunition. Most of it just shifted vertically up, which I have no problem with. I hate horizontal shifts. I used Wolf 55gr FMJ, Tula 75gr BTHP, ZQI 62gr SS109, Gold Dot 55gr, 64gr, and 75gr BSP. Aim center mass and all of my ammo will hit 2" high at 100 yards or higher! (I zero ~1-2" high at 100 yards).


1st image is my setup!
2nd image is my 8 shot group with Gold Dot 64gr, my shtf and home defense round. If you ignore the two fliers, you get around 1.4 MOA. Pretty good!
3rd I wasn't trying as hard to get a tight group; I was testing to see how the different weights of 55gr and 75gr Gold Dots would perform. So the groups weren't too tight, but 5 shots of each weight gave me that group. I got a few hundred in those weights and I know if I had to use it, it hits dead on or generally a few inches higher.
4th is my 10 shot group with ZQI 62gr SS109. I was satisfied with the results. Roughly 3 MOA and I know the round isn't designed to be too accurate. I've shot these with my 24" AR before and got around the same size groups, so I'm happy that the Tavor can shoot the same.

Considering I used a red dot, on very high brightness, and just a piece of wood for the front and my left hand to stabilize the rear, I'm very happy with the results. Gun has over 3k rounds through it, 2k at least are steel.

LAST THREE IMAGES sideways... Don't know how that happened...just tilt your head  Cheesy


* IMG_0847.JPG (3273.37 KB, 4032x3024 - viewed 37 times.)

* IMG_0845.JPG (1923.37 KB, 4032x3024 - viewed 17 times.)

* IMG_0846.JPG (1829.79 KB, 4032x3024 - viewed 16 times.)

* IMG_0848.JPG (3149.82 KB, 4032x3024 - viewed 18 times.)
« Last Edit: January 12, 2018, 10:38:39 PM by SteveD » Logged
Jwill
Member
**
Offline Offline

Posts: 74


« Reply #1 on: January 11, 2018, 05:07:01 AM »

I suppose the ones to ask would be aac.
Logged
SteveD
Member
**
Offline Offline

Posts: 104


« Reply #2 on: January 11, 2018, 05:12:43 AM »

I know they don't recommend their muzzle brake. I saw an old post I believe gearheadworks said they personally use the jam nut as their "shoulder" and use a shim to time it. Just wondering if someone has experience with overtorqueing their break this bad/ possibly same setup as me. Guess this post may be an accuracy test  Grin
Logged
xdmikey
.
Sr. Member
***
Offline Offline

Posts: 358


« Reply #3 on: January 11, 2018, 07:26:02 AM »

I use the 51T on all my rifles but I'm using a Saker 762 & 556.

I don't remember a lot of concern about timing or torquing too much but I did use shims as well. And rockset.

Let me know if you need more info.
Logged
SteveD
Member
**
Offline Offline

Posts: 104


« Reply #4 on: January 11, 2018, 05:15:43 PM »

Did you use the muzzle brake version? AAC doesn't recommend it because it requires the use of the barrel nut since the threads on the barrel are longer, and I suppose they are worried about baffle strikes. I guess they think the nut jammed against the brake may work itself loose during use and barrel flex. However I jammed the nut against the shoulder and the brake is smushing it, so it's not going anywhere.
Logged
SteveG75
Member
**
Offline Offline

Posts: 71


« Reply #5 on: January 11, 2018, 05:48:23 PM »

You should not be using the jam nut to index the muzzle device since it does not assure concentricity. The issue is that the jam nut surface is not ensured to be 100% perpendicular to the bore.

If you are really concerned with alignment and want to use the jam nut. you can screw the jam nut all the way on, screw the muzzle device on, and then back it off to an aligned position then tighten the jam nut to 25 ft lbs. I have heard that AAC does not recommend jam nut use.

I used a KBA Custom Tavor Muzzle Shoulder Ring to mount the flash hider for my Rugged Suppressors. Alignment is perfect with a 9" long can using the 5.56 end cap. You could use that with the Precision Armament's Accu-Washer system to get a brake aligned. Personnally, I don't see a need for a brake on a Tavor.

Here are some links to the Muzzle Shoulder Ring. Worth the $29.

https://www.kbacustom.com/our-products/firearm-accessories/product/37-tavor-muzzle-shoulder-ring.html
http://www.capitolarmory.com/tavor-muzzle-shoulder-ring.html

Some great pics at the KBA Customs Link and a good explanation of why not to use the jam nut as a shoulder.

Logged
SteveG75
Member
**
Offline Offline

Posts: 71


« Reply #6 on: January 11, 2018, 06:59:07 PM »

Did you use the muzzle brake version? AAC doesn't recommend it because it requires the use of the barrel nut since the threads on the barrel are longer, and I suppose they are worried about baffle strikes. I guess they think the nut jammed against the brake may work itself loose during use and barrel flex. However I jammed the nut against the shoulder and the brake is smushing it, so it's not going anywhere.

The problem is that the jam nut is not ground perfectly concentric. So, by jamming the nut against the brake, you can induce some alignment issues.

Also, do you have an alignment rod to check overall alignment with the can mounted? I have a Giessle alignment rod and it was worth the $$$ when I found out that the threads on my Mossberg MVP were not concentric to the bore. Had to send the rifle back to Mossberg to get new barrel but saved myself a baffle strike.
Logged
SteveD
Member
**
Offline Offline

Posts: 104


« Reply #7 on: January 11, 2018, 07:07:41 PM »

Call me cheap but I can't see myself spending $65 on a Giessele Alignment rod. However, there are cheaper ones on Amazon for $12 that I might try...
Gonna test for groups with just my brake right now; not really concerned with baffle strikes there. Once I get the can in I'm going to visually inspect and try the rod.
Logged
SteveG75
Member
**
Offline Offline

Posts: 71


« Reply #8 on: January 12, 2018, 08:13:05 PM »

The Giessle rod is expensive but cheaper than a baffle strike. Discovered that the threads on my Mossberg MVP were not concentric to the bore. Had to send that rifle back to Mossberg to get a new barrel.

Maybe someone local to you has one you can borrow.
Logged
xdmikey
.
Sr. Member
***
Offline Offline

Posts: 358


« Reply #9 on: January 13, 2018, 08:19:32 AM »

I just bought a dowel that fits tightly into a 223 case and ran it through the barrel and suppressor.
Logged
konigstigerii
Member
**
Offline Offline

Posts: 13


« Reply #10 on: January 13, 2018, 12:57:09 PM »

I have used the Jam nut with the 51t brakeout 2, and the blackout, no shims, use the nut to index. On both a 16.5 and 18 inch barrel, with a 556-SD can. No issues what so ever.

My X95 is very overgassed with the 556-SD, I recommend buying the shooting sight extra power spring, it helps with the bolt not bottoming out as hard.
Logged
SteveD
Member
**
Offline Offline

Posts: 104


« Reply #11 on: January 13, 2018, 03:46:48 PM »

Thanks for the responses. I bought a $12 .2175 diameter 36" rod on Amazon, and I purchased the extra power spring and installed it a few weeks ago. I'll ask my friend when my can comes in if he bought the geissele rod since he owns a SilencerCo Omega, as reassurance.
Logged
MajorKong
Member
**
Offline Offline

Posts: 21


« Reply #12 on: January 13, 2018, 05:17:49 PM »

You should not be using the jam nut to index the muzzle device since it does not assure concentricity. The issue is that the jam nut surface is not ensured to be 100% perpendicular to the bore.

If you are really concerned with alignment and want to use the jam nut. you can screw the jam nut all the way on, screw the muzzle device on, and then back it off to an aligned position then tighten the jam nut to 25 ft lbs. I have heard that AAC does not recommend jam nut use.

I used a KBA Custom Tavor Muzzle Shoulder Ring to mount the flash hider for my Rugged Suppressors. Alignment is perfect with a 9" long can using the 5.56 end cap. You could use that with the Precision Armament's Accu-Washer system to get a brake aligned. Personnally, I don't see a need for a brake on a Tavor.

Here are some links to the Muzzle Shoulder Ring. Worth the $29.

https://www.kbacustom.com/our-products/firearm-accessories/product/37-tavor-muzzle-shoulder-ring.html
http://www.capitolarmory.com/tavor-muzzle-shoulder-ring.html

Some great pics at the KBA Customs Link and a good explanation of why not to use the jam nut as a shoulder.



Just wanted to say thank you for providing this information. 

Logged
Pages: [1] Print 
Jump to:  



Login with username, password and session length

Powered by MySQL Powered by PHP Powered by SMF 1.1.21 | SMF © 2015, Simple Machines
SimplePortal 2.3.5 © 2008-2012, SimplePortal
Valid XHTML 1.0! Valid CSS!