Just an aside - I have a bunch of Checkmate 7-rounders (current Colt-spec) that I bought bulk at discount and one Colt 7-round made by Okay Industries. Those and the 7-round mag that came with my SR1911 are identical near as I can tell, right down to the follower - and all run perfectly in the SR1911 and in the Rock Island that my son now has. The Ruger 8-rounder with extended baseplate and follower to match, with very similar "hybrid" lips, also runs perfectly.
The Act-Mag eight-rounders (extended base, wadcutter lips, smooth follower) that came with that Rock Island and a few others bought separately would occasionally bobble that last round in the RI - but run perfectly in the Ruger.
