I just found a 'suppressor' thread
Okay, don't know if there is a more recent one but i found this first.
Would suppressors reduce recoil?
Suppressors reduce firing recoil significantly, primarily by diverting and trapping the propellant gas. Propellant mass is generally a fraction of the projectile mass, but it exits the muzzle at multiples of the projectile velocity, and since recoil energy is a function of mass times velocity squared the elimination of the propellant recoil can be significant. Paulson et al., discussing low-velocity pistol calibers, suggest the recoil reduction is around 15%
http://en.wikipedia.org/wiki/Suppressor Although this could be false since most people troll and give out false information. But it could slightly reduce recoil. I would like to see reduced recoil.