not quite muffs loud but close compared to ny other rifles . the thing is the air brake is epoxied on so i would have to heat and clean up after glue melted and really i do not want to heat up the end of the barrel that hot .
I always liked to hear the USFT fire.. to me it was more of a nice pop... Then when ran across the chrony it was shooting much faster than when thought too.. I tune a rifle I never have a moderator on.. when I hear a nice snap or pop... I know I'm real close to where it's gonna be happy... mod installed it's near silent
As @Jasonmc commented, they do have a "pop" sort of sound wth just the bare barrel. The "strip T's" brake that Tim puts on them makes it seem even worse than it really is.
I bought a 16mm to 1/2x20 adaptor, as others have suggested. With a 30mmx7 inch moderator it'll be so quiet you wonder if it's still shooting at the correct speed. After a couple years I swapped out the 7inch moderator for a little Huggett Atom. The Atom isn't nearly as quiet, but it's plenty quiet for most backyards, and, as they say, pellet smacking the target is louder. Shaved 3.5 to 4 inches off the overall length so the trade off was worth it to me.