I've been shooting my brass 1858 (Pietta) for over 3 years now(probably about 250 rd per year) and there has been ZERO issues with it. I usually load the max 30gr BP load with ball or 180gr conicals on ocassion too.
I fully expect this gun to last as long as me; and I'm hoping to get another 35 - 40yrs out of this old body.