Sharpshooter not getting damage increase?

Hey I was kinda skeptical on the damage increase part of the sharpshooter perk when I noticed it takes the same number of non head-shots to kill a clot with the 9mm as it does for the other classes. Just tested solo gamed hard difficulty counted 5 shots in body to kill clot with my lvl 1 beserker, and 5 shots to kill with my lvl 5 sharpshooter. Whats going on?