Need help with hp max muzzle brake.

[bearair]

I just got a muzzle brake from Bintac and when it's screwed on all the way it sets not quite square with the barrel. Looking for some ideas how to get it to sit right with the barrel. TIA. I did put an oring on the barrel and have it cinched down pretty good and all looks good and feels snug. Is this safe?

 

[Miami Airgunner]

Spacers, you can just make your own crush washer from wadded up aluminum foil, but the commercial ones are best.

 

[bigHUN]

Cone disk washer, spring washer, beleville washer ....