"Silencers" aka "moderators" aka "mufflers" aka "can" are all the same thing, a suppressor to lessen the sound from the muzzle of a gun.
The debate over wheelguns v semis being silenced rages on. The cylinder gap on a revolver lets noise escape, and so does the slide on a semi.
I personally have 3 host guns for 1 suppressor, all in .22lr. When I shoot with the suppressor, I shoot subsonic ammo for max effect.
One of the guns is my Ruger 10/22. I heavily modified it - custom stock, Tactical Innovations barrel, tuned bolt, trigger job, Pride-Fowler BDC scope, and even a BOLT LOCK to hold the bolt closed, thus making a semiauto into a single shot - and when I am not shooting just for fun, I use it for urban pest control. There is a long history of silenced rifles being used for pigeon and rat control in cities. Most of Europe does not regulate moderators.
I paid ~$190 for the suppressor, and adaptors for two pistols ran ~$70. The 10/22 barrel was being replaced for other reasons, and having the end threaded was included. The only other expenditure is $200 for the Class III tax stamp from the BATFE.
My opinion is that ear muffs are clunky and unwieldy, and hot. Suppressor is light and cleanable. Ear muffs work for me, silencer works for me and my neighbors.
If you are really interested, try this place-
http://www.silencertests.com/
Merry New year, y'all.