One of the most impressive suppressed firearms I have seen was a Ruger 10/22 with a little 1"x6" AAC silencer. The bolt clacking was seemingly louder than the muzzle report. There are less noisy firearms out there, but they are suppressed bolt action rifles or integrally suppressed guns with ported barrels that reduce velocity, sometimes to a substandard level. I have a 51 caliber subsonic carbine with a 2"x18" can on it. It suppresses a load of 30 grains of H110 enough to make it sound like a car door slamming instead of a gunshot, but it is not as impressive as a good suppressed 22 rimfire.
That said, Al Paulson's Silencer History and Performance states that a 10/22 bolt closing on a cartridge is about 100 decibels, while the muzzle blast is about 115 decibels. The muzzle blast seems quieter because it is of such short duration and farther from the shooter's ear than the bolt. If you are paying attention to a normal conversation at the shooting bench with another person, you might not be aware that the shooter was shooting anything.
From what I have read about others who have gunsmiths thread their barrels; if the barrel is easily removed from the gun, then it usually costs less than $50 to thread it on a lathe. A skilled gunsmith uses a lathe instead of a die to ensure the threads are aligned with the bore. I use a tap and die for anything less than one inch because I am not a skilled gunsmith.
My 10/22 would not reliably cycle with subsonic ammo when using the stainless barrel it came with, but it did fine with the $20 blue Ebay barrel I bought for it. The stainless barrel might have a rougher chamber, not sure why.
Ranb
ETA; the Buckmark and S&W pistols are very popular to suppress. 9mm's are also popular, but most of them need a recoil booster to decouple the weight of the silencer from the barrel upon firing to allow the slide to operate correctly and pick up the next round. The Berretta 92's do not as the barrel does not tilt and is not affected as much. I made a silencer for my Browning HP. It is not an ideal host as the barrel is quite slim and there is no shoulder for the end cap to index on to maintain proper alignment. I had to simply make it a tight fit on the tiny portion of the barrel between the threads and the front of the slide. I was able to make it light enough to use without a recoil booster. But I had to load the 147 cast bullets above the max load in the book to 1060 fps and use a cut down 8 pound spring to ensure proper operation.
As far as I know there are no 45 ACP pistols that will function properly without a recoil booster. They are also noisier than most suppressed 9mm's due to the larger bore when both are shot dry, but they are significantly more powerful when subsonic ammo is used as the bullet weight is typically 230 grains vs 147 grains.
Shooting suppressed is a nice experience. Under the right conditions, it is possible to do without using any other hearing protection at all and still be safe on the ears. While ear muffs and plugs have their place, it is delightful to shoot without their numbing affect on your hearing. This is something that certain self loathing gun owners enjoy, but do not want the rest of us to experience.
