Gunsmithing Removing metal shim?

[kthomas]

I'm trying to change out the muzzle device on my wife's ar15, and it has a big metal shim, that oddly seems to have the same ID as the OD of the threads. I'm not familiar with these types of shims, and I'm not sure if there's any tricks besides cutting it to get it off (maybe heat it up to expand it?).

Here is what I'm talking about:

This is about as far as I can get it:

 

[1moaoff]

Are you positive the shim isnt threaded?

 

[rgv]

That’s a standard 1/2” crush washer.

When they get crushed more than half a turn or so they can be difficult to remove.

I’ve used a Dremel and cutting wheel, but usually you can grab them with vise grips and thread them off

 

[dustingaunder]

Yeah just thread it off with some pliers. Its soft and shouldn’t hurt anything. Dremel cutoff is an option but might not end well if you slip.