So I just got my Mark 3 .22 sniper and I chose to get a 30 cal Donnie FL because I want to get a 30 cal Barrel kit sometime soon. And you need an adapter because the 30 cal is larger I'm not sure what that thread is but Jim at Precision airguns gave me an adapter that went from the 1/2 20 UNF up to whatever the 30cal is. and by the way it is just as quiet as my daystate Huntsman shooting the same velocity even with that larger 30 caliber hole