In the 1960's the Columbus, Ohio PD conducted "drop tests on 1911's. With an unmounted slide, using a primed case, over 50% of the time it went off! With the slide mounted to a GI firearm, and a loaded magazine they never once got one to fire when dropped from 5 feet to 19 feet in the air. Mostly, they landed on the lanyard ring/ loop. I believe the troubles start when untrained people do "Action Jobs" and other tricks to the safeties, and the pistols weren't safe to start with! I built one from GI parts, that would fire with the grip safety in the safe position. A more experienced friend fixed the problem by using Cold sear and disconnector. With the "loose" GI part specs they could have a "perfect storm" and not be safe but Colt specs always kept things the way they were intended. After that point all my guns were built with Colt or Wilson sears and disconnectors. A few thousandths here or there can add up to a failure in a hurry!

(BTW: The extra cost was about $3 per pistol, buying retail! Easy and affordable fix!)

Ivan