Suppressors Griffin Checkmate QD threads not fitting barrel

[sentry1]

Has anyone used a Griffin Armament Checkmate QD adapter? My CZ455 barrel is threaded 1/2x28, and I just got in two of the Checkmate QD adapters direct from Griffin. Neither of them will thread on: I can’t get a full turn before the adapters jam up. Tried elbow grease the first time, ended up needing pliers to unscrew it.

A 1/2x28 thread protector screws onto the barrel just fine, so I’m confident I’ve got good threads there.

 

[SDet]

Muzzle devices are held to a much tighter standard than thread protectors. Either try the muzzle devices on a different 1/2-28 barrel, or try a different suppressor mount on the cz. That's the easiest way to check without an actual gauge. Just don't force anything.

 

[blcouch]

I’ve used both an original (bought with can in 2008) and a new (bought from Modern Outfitters in 2016) QD mount for my Checkmate. Both went on threaded barrels just fine (Beretta 21a and Mosquito Gemtech barrel). The quality of the 2 different mounts was top notch as was the fit even though bought 8 years apart.

 

[sentry1]

I’ve used both an original (bought with can in 2008) and a new (bought from Modern Outfitters in 2016) QD mount for my Checkmate. Both went on threaded barrels just fine (Beretta 21a and Mosquito Gemtech barrel). The quality of the 2 different mounts was top notch as was the fit even though bought 8 years apart.

I'm going to take it by a competent gunsmith this week and get it checked out. The thread protector screws on snug without any play, so I don't think it's poor tolerance on the threads. Hopefully he can just clean up the threads on the adapter and I'll be good to go.

 

[bpair]

Factory threaded barrel? I have a factory threaded CZ455 and had an older QD thread right on. But, im with the other guys and check on barrel threads. Ive had factory threaded barrels before that would not let my Thunderbeast screw on (who im told are very tight tolerances). I had it cut and re-threaded, screwed right on.

 

[SDet]

I'm going to take it by a competent gunsmith this week and get it checked out. The thread protector screws on snug without any play, so I don't think it's poor tolerance on the threads. Hopefully he can just clean up the threads on the adapter and I'll be good to go.

If the thread protector is tight, the threads are much too big.

Thread protectors have 0 stress on them, so oversized threads will guarantee fitment without affecting the performance. On a suppressor mount, you'd lose strength by cutting the threads large only to accommodate poor thread jobs.

TBAC uses class 3 threads, so, the tightest standard spec, but they'll work with any properly cut class 1 or 2 threads. Just no room for out of spec threads.

 

[sentry1]

Factory threaded barrel? I have a factory threaded CZ455 and had an older QD thread right on. But, im with the other guys and check on barrel threads. Ive had factory threaded barrels before that would not let my Thunderbeast screw on (who im told are very tight tolerances). I had it cut and re-threaded, screwed right on.

Threaded by a gunsmith, the same one who did the work to turn my .308 R700 into a 6.5 Creedmoor.

Griffin returned my call pretty quickly, they said that the hard coat anodizing may get thick on the threads, and are shipping out a set that they checked for fit already. Either way, I'll have all the threads checked and find out where the problem is.