How far to shim?

**doc_ralston** · 08-24-19, 17:01

So I'm looking to build an upper receiver with a STNGR RPTR hand guard, and the shortest they have is 8.25 inches, which is just what I want. I run an SDN6 currently, and it has a pretty good gap between the can and the hand guard. I really want the suppressor as close as possible, but I'm concerned that 8.5 inch barrel would be too short to shim the brake out. Any advice would be greatly appreciated!

Current gap between hand guard and suppressor. 8.5 inch hang guard with a 9.5 inch barrel.

Different rifle with 11 inch hand guard and 11.5 inch barrel

**556BlackRifle** · 08-25-19, 10:30

Doc, by taking crude measurements off the computer screen, you might be at the limit. Have you thought about a combination of shims and trimming a little material off the front of the handguard?

Good luck.

**rjacobs** · 08-25-19, 10:39

I would never shim a suppressor mount further than required to clock it appropriately at the recommended torque.

You are talking like a 1/2" shim I believe...no...

2 reasons(and im sure more):
thread engagement will be sketchy...at best...
alignment would be questionable also...

Find a 9" hand guard, buy a 9.5" hand guard and mill off the front to your liking, change barrel lengths or have your barrel cut down slightly and re-threaded.

I guess I am more of a function over form kind of guy though so your current setup(8.5" handguard on 9.5" barrel) looks good to me.