I had the muzzle device hand tight on the barrel and threaded suppressor on hand tight. I cannot get it out of the suppressor now. I took the suppressor apart and can grab the MD with a pair of needle nose pliers, but they just spin on the MD without breaking it loose. Anybody have a suggestion?

Is that the Griffin?

Yes.

Run a bolt through a rubber bushing that will fit inside the threads on the muzzle device. You’ll need a bushing that extends beyond the threads on each end and a tight fit to begin with. Tighten bolt/nut so the rubber will expand into the threads. Once tight, you should be able to remove the MD by turning the bolt on one end.

I ended up using Loctite to get it off. That was a PITA. Thanks for the suggestion.