I have fired countless rounds of 555 and don’t recall having any trouble. Same with Federal bulk. I used to use a 10/22 for gopher shooting, maybe had a few that didn’t have the same snap to it, more noticeable in a semi. I use CZ 455’s and now a 457. The past. three days I have fired a pile of Herter’s, 555, Federal bulk, and Aguila Super Extra, all in a St. Patrick’s 455. Poor thing is getting rather dirty. Tomorrow I’ll crack out the 457.