The SA mil spec is very close to the original 1911A1. The front strap on the grip is more squared (like all SA's) than the Colt. The slide serrations are angled instead of vertical. It does not have the firing pin safety that the Colt Series 80 has. My SA has a stainless barrel and bushing. The newest SA's have the main spring locking device that SA started installing earlier this year. I'm sure there are other guys with both pistols that can add further details.