Shims Causing Suppressor Alignment Issues

[Swab]

Not with this device/combo but I've crushed the crap out of shims so badly they "squished" out of round.
(I think squished is the correct, scientific term)

It is correct, I squished the **** out of the .002" ones at 40 ft lbs

 

[IMDB]

It could be the rifle thread that's the issue,not center of the bore. What suppressor do you have?

 

[Swab]

Swab
There have been a few replies already over on the arfcom page. Check it out

Griffin Taper Mount - Shims Causing Suppressor Alignment Issues paging Green0 - AR15.COM

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This is cool, thank you. One of the griffin owners is on to something (as well as another poster), I gotta go eat with my family or they will disown me. I'll be back shortly.

PS: Don't be fooled by those ARF.com dudes...they will roll you in a second

 

[AK74U]

In for details.

 

[Swab]

The rifle is a Bergara Wilderness and has their #5 contour barrel so it has plenty of shoulder. Sounds like it could be the thread relief and the shims not staying centered. Not sure how I’ll keep them centered when torquing but I’ll give that a shot.

I’m pretty impressed that the owner of GA responded so quickly and with a good amount of detail. Thank you Glockspeed31 , maybe I shouldn’t be so hard on those guys on that site, they seem pretty nice…maybe.

 

[BigMike]

Just a thought, but get a flat washer and true it with a piece of glass and sandpaper. Then keep sanding until you have it timed correctly. The shims will mash out and get goofy.

 

[fast306stang]

Some AR barrels have a contour on the shoulder of the barrel. You have to use a chamfered shim with a concave side to mate with the shoulder of the barrel first, that gives you a "true" side to stack your shims. A Surefire pack of shims comes with everything you would need. Is it possible your barrel has the contour?

 

[Swab]

Some AR barrels have a contour on the shoulder of the barrel. You have to use a chamfered shim with a concave side to mate with the shoulder of the barrel first, that gives you a "true" side to stack your shims. A Surefire pack of shims comes with everything you would need. Is it possible your barrel has the contour?

No, sorry, I should have specified this I initially. This is on a Bergara Wilderness.

I have no issues when I don’t use shims. Once I add the shims to get timed correctly is when the issue pops up. Also, the .002” shims are visibly “smashed” afterwards.

I’m at hunting camp now so I’m gonna have my buddy help me and see if I can keep them concentric with an extra set of hands.

 

[Swab]

It could be the rifle thread that's the issue,not center of the bore. What suppressor do you have?

It’s a Griffin Sportsman. It’s definitely the shims, When I install the brake with no shims, it’s perfectly fine.

 

[fast306stang]

Also, the .002” shims are visibly “smashed” afterwards.

This doesn't sound right either, you should be able to torque the mount to spec without the shims deforming. I'm still scratching my head on this