Hank here's a picture of the two 255gr cast bullets I load in the .45acp. The one on the left is a LEE #90358 (.452-255 RF) and the right one is a 'commercial' Keith-style swc. Neither are gas checked and I've not had any leading problem in my .45's, colt or acp. In the colt, I run them with 10.0grs unique and get an average of 1050fps(5'5", ss, Ruger Bisley NMBH). I haven't chrono'd them out of the acp, but I'm guesstimating 750-800fps. They both 'feed and cycle' well in the acp.
Sorry the pics are not 'courtroom' quality, but my little digital camera is only 5mega pixals.
The LEE actually has a larger melplate that the swc.