I think Steve's "tongue-in-groove" explanation is the one that I've heard most, although I've also heard folks complain about the right-side safety getting in the way.
As a lefty, I'm sort of SOL with Mr. Browning's most enduring invention. The gun is set up so that I have a choice of a (weaker, tongue-in-groove connected) ambi safety, or nothing (Josh, I've never seen a left-handed-only safety, but the way the 1911's designed, such would require that the right-handed parts on the left side still be left in place to interact with the sear). (I suppose I'm forgetting about those unusual "Portsider" mirror-image 1911s, but those are pretty rare.)
I'm really not a fan of the ambi safety on the 1911, because they all stick out pretty far, and I really don't like the feeling of my thumb jouncing on it during recoil - although this is
much more annoying for me with a super-lightweight gun such as a Micro-Compact SA with an alloy frame than it is with a full-sized steel-framed 1911.
I've thought about carrying the 1911 with the hammer down on a loaded chamber, but there are just all kinds of problems I can see with that in terms of safety,
PLUS the fact that it would be somewhat slower to get into action.
Teddy Jacobson, a gunsmith who certainly knows what he's talking about, is also a southpaw, and he is most assuredly not a fan of the ambi-safeties. I'll have to go over to his site again and see how he handles this.
OT - I just saw two
terrific deals on 1911s at a local shop (an IPSC guy was trading out old guns to get $$ for new ones), and it's really hurting to not run over an buy them. :-/ The best deal is a super-tricked out Springfield Armory (U.S. frame) with an extended Heinie barrel and comp, Bo-Mar adjustable night sights, and all kinds of other neat stuff for $550. The other one, still a good deal, is a Michigan Armaments Custom Combat for $400. I got out Steve's
Shooter's Guide to the 1911 Pattern Pistol last night, hoping that reading it a bit would help me get over wanting to go pick up one of these pistols. (I know, that was probably not a good plan!

) It didn't help - I still want to go buy one of them. :-[ Fortunately, I have a friend who's looking for a good 1911, so I've steered him into the store, and maybe he'll beat me to the unbeatable deals.
