Well, the first thing about a suppresor is; they don't work well with revolvers.
There is a gap between the cylinder and the barrel that would allow a lot of sound to escape. I know if you watch a lot of TV -- especially old TV, like Mannix, Naked City, The F.B.I. and others, you may have seen a lot of "silenced" revolvers, usually snubbies.
That's TV. They don't use real suppressors even when they have semiautos -- they have a phoney prop and dub in the sound, which is why people who do know what suppressed weapons sound like often complain about the fact the TV show is not realistic.
The best BP gun to try to silence would be a muszzle loading single shot.
But, you'd still mess the silencer up very quickly, as the 2nd poster said .....