Shims, crush washers... both? SF3P

[Naaman]

This is my first time attempting any kind of "build" from parts.

I've got an upper I'm working on and would like to try running some drills with it with a few different handguards.

I have a SF3P that will be going on it, and looking to buy some extra crush washers for when I swap handguards.

The muzzle device comes with one shim kit (which includes a crush washer), and some Rocksett.

Should I Rocksett the muzzle device each time before deciding on a handguard, or just wait till I've chosen the final configuration (does applying Rocksett affect the performance of the barrel/muzzle device combo)?

Also, my reading seems to indicate that shims are an alternative to crush washers, but also that the shims are for timing and crush washers are for tension. Can the SF3P be properly installed with just the shims and Rocksett, or is the crush washer necessary? It seems like the shims are reuseable. Is that correct?

 

[Lucreau]

Wait til you have the rail you want. And there isn’t a crush washer in that surefire kit, it’s just shims. Use only shims

 

[Gasgun]

That isn’t a crush washer.
It is used on barrels that do not have a relief cut at the base of the muzzle threads.
SureFire sells shim kits if you need more.
Use the Rocksett. It doesn’t negatively affect performance.

 

[Naaman]

Thanks, guys.

 

[Waorani]

If you're not putting a suppressor on it, an actual crush washer is fine and will allow easy removal until you settle on handguard. Shims if suppressor going on to start.

 

[JsnSanko]

Is there any difference in accuracy (all things being equal) between shimming a muzzle device or using a crush washer?

Asking (for a friend-me) on a Ranier Ultra Match Barrel I can’t (and have had others shoot) get better than 1” anything I do. It does 1-1 1/4” always. Boringly always. Wondering if removing the muzzle device and using shims instead might help.

 

[Sincerd]

Is there any difference in accuracy (all things being equal) between shimming a muzzle device or using a crush washer?

Asking (for a friend-me) on a Ranier Ultra Match Barrel I can’t (and have had others shoot) get better than 1” anything I do. It does 1-1 1/4” always. Boringly always. Wondering if removing the muzzle device and using shims instead might help.

May try. I don't think anyone can guarantee what the issue is. Just process of elimination. Ammo, optic, shooter, barrel.

 

[alamo5000]

Is there any difference in accuracy (all things being equal) between shimming a muzzle device or using a crush washer?

Asking (for a friend-me) on a Ranier Ultra Match Barrel I can’t (and have had others shoot) get better than 1” anything I do. It does 1-1 1/4” always. Boringly always. Wondering if removing the muzzle device and using shims instead might help.

It 'can' cause problems but in your case there isn't enough information to make that determination. A shim set is superior in my opinion because it's designed to keep everything square, especially when shooting suppressed. The crown of the barrel is a very key component of the barrel itself. When you put a muzzle device on a rifle you are basically creating a new crown. If it's not square it can lead to problems.

Personally though I think there isn't enough information for anyone on the internet to solve your problem. There are 900 variables that it could be so at best it's a guess.

 

[Naaman]

It 'can' cause problems but in your case there isn't enough information to make that determination. A shim set is superior in my opinion because it's designed to keep everything square, especially when shooting suppressed. The crown of the barrel is a very key component of the barrel itself. When you put a muzzle device on a rifle you are basically creating a new crown. If it's not square it can lead to problems.

Personally though I think there isn't enough information for anyone on the internet to solve your problem. There are 900 variables that it could be so at best it's a guess.

Are we talking about the torque on the barrel or are we talking about the muzzle device physically interacting with the exiting bullet?