I shot IPSC, seriously, for several years back in the seventies. I, early on, learned to discard R-P brass. I was a formally trained machinist, back in the day, and after measuring R-P brass discovered the problem was very simple. R-P brass was entirely, and measurably, TOO thin. I discarded all R-P brass. My favorite brass, at the time, was military brass. It had "crimped-in" primers that required swaging the primer pockets, but that was a one time thing. Today, Starline brass is an excellent choice. I size all bullets at .452" (that is proper for my 1911's as well as my .45 ACP revolvers). I use the Lee Factory Crimp Die, and taper crimp to an outside diameter of .470" on my Dillon 550B, and have NO issues these days. NO R-P .45 Cases for me!
Dale53