How can I securely attach a muzzle device without a crush washer?

[Gundam]

I have a Saiga that was converted to look like an AK, and recently bought a PWS JTAC47 compensator for it. Unfortunately my Saiga does not have the retaining pin in it's front sight block, which would be the normal way of attaching a muzzle device. I've emailed PWS and they said that crush washers for the 14mm size muzzle don't really exist and suggest I look at a hydraulics/fitting supplier or industrial hardware store. I don't really want to chase all over town/internet to find something that may or may not work.

Is there any other way I can attach my muzzle device that is not permanent? I would hate to pin and weld when I absolutely do not have to. Would Rocksett work in this case?

[69Mach1]

Hardware store for a tension washer, or rubber O-ring. heavy duty O-ring.

[Gundam]

Hardware store for a tension washer, or rubber O-ring.

The PWS comp came with a little red polymer ring, but I don't think it is capable of securing the comp or else they would have stated so in their email back to me.

http://primaryweapons.com/store/pc/viewPrd.asp?idproduct=15&idcategory=6

[sevensix2x51]

Well, im not really sure how -AN fittings correlate to metric thread sizes, but I would look at those copper washers for banjo fittings... like the ones on brake caliper lines, but bigger... so id have to second the suggestion from pws. If hose pros ain't got it, it may very well not exist.

[ojisan]

Try an aluminum crush washer for an auto oil drain plug.
Should work fine and be cheap....auto parts store or good hardware store will have them.

[Gundam]

Try an aluminum crush washer for an auto oil drain plug.
Should work fine and be cheap....auto parts store or good hardware store will have them.

Hmm I have several crush washers for AR15's at home. I'm wondering if I can dremel it out to fit the AK muzzle?