Let me ask you this: Do you know anyone who carries an M1911 on half-cock?
Probably not -- because the half-cock on the M1911 is just as dangerous as the half-cock on the Colt Single Action. Everyone I know who carries an M1911 carries it cocked-and-locked.
The John Browning pistol, the M1910, that passed the field testing and reliability testing had a half cock . This is what John Browning says in his patent:
Patent 984,519 J. M. Browning, Firearm,
application filed Feb 17 1910. Patented Feb 14 1911.
Page 7
Heretofore in the pistols of this class, when the hammer was cocked ready for firing, and it became necessary to lower the hammer to the safety position without allowing it to touch the firing pin, it required both hands of the user to accomplish this act, because the trigger had to be pulled with the first finger of the right-hand to release the hammer and the grip-lever had simultaneously to be pressed into the grip to release the trigger for operation, to the keeping of the thumb of the right hand in a horizontal position on the side of the grip. Therefore it was impracticable to also extend the thumb of the right hand, while this hand pressed in the grip-lever and pulled the trigger, upward so as to rest upon the thumb-piece of the hammer and, thus controlling the hammer, to gently lower the same and restrain it from falling and from striking the firing pin, because any attempt to do this would result in loosening the necessary hold upon the grip-lever. Consequently the lowering the hammer had to be performed by the other hand, this is a serious drawback in a military arm, as a soldier and especially a mounted soldier does not in action have both hands free for such use. To overcome this difficulty, I have provided the grip-lever w with projecting nose w2 in rear of its pivot, which stands closely in rear of and below the hammer when cocked, and the hammer is so fitted that it may be drawn rearward somewhat father than to its cocked position. When the hammer is drawn fully back it strikes the nose w2 and, by pressing the same downward, it caused the grip-lever to turn on its pivot forcing the lower portion into the grip, thereby releasing the trigger. By this arrangement the thumb of the hand grasping the grip needs not to be kept at the side of the grip need not to be kept at the side of the grip for pressing in the grip-lever, but the thumb may be applied to the hammer and through the same operate the grip lever to release the trigger, then the trigger may be operated with the first finger of the same hand to release the hammer and finally the thumb, still applied to the hammer, may allow the same to slowly descend to the safety position, without requiring the aid of the other hand. The rearward projecting nose w2 of the grip-lever w below the hammer q and in rear of the pivot pin w1, serves to perform another important function in addition to that of providing the point of contact between the grip lever and the hammer, by means of which the grip lever may be operated to release the trigger by drawing the hammer fully rearward, as here in before described.
From what I read, the Army wanted a grip safety so the pistol would not discharge if dropped, from a horse. This was before they insisted on the "make safe with one hand" requirement, that lead to the thumb safety. The pistol that passed all the tests, the 1910 Colt, did not have a thumb safety, it had the grip safety.
Links and pictures from Sam Laker’s ColtAutos.com
http://www.coltautos.com/default.asp
This is an exceedingly rare pistol, Sam has pictures of serial number 2, and it is not retrofitted for the thumb safety, and this one, serial number 5, is in the original 1910 troop trails configuration.
There is a prior history. This is the M1903 patent picture
There is no thumb safety, this pistol was made safe by lowering the hammer to the half cock. Also, John Browning designed the 1903 trigger mechanism so when the hammer was at half cock, the slide was fixed in place. That way, you would not jack out a round while holstering the thing. This feature is retained in the series 70 M1911. You can test it, in a series 70, by lowering the hammer to half cock, and trying to rack the slide. You can over ride it, which I assume was intentional, but the resistance is there, and it is not accidental. John Browning put it there. No one ever does this, so guys at the range are amazed when this feature is shown to them.
The Army must have thought that lowering the hammer to half cock was too difficult, with one hand, and a bucking horsey, they wanted something simpler and more positive.
John Browning did design a sear blocking thumb safety, or his pistol would never have been accepted by the Calvary, who wanted to keep their revolvers. And he designed an improved half cock, that would prevent the hammer from falling if the sear broke. It is possible to break the sear on these pistols, by hitting the hammer hard enough. However, not all of his 1913 patent was accepted for use by the Army, and they did not use the new and improved half cock safety.
This feature was never incorporated into the issue 1911. I don't think the Army trusted making the pistol safe by lowering the hammer to half cock. Both the Army, and John Browning understood the thumb safety was there, so the pistol could be quickly, and temporarily made safe, until such time as the hammer could be lowered, all the way down.
Half cock safeties have been used on muskets, lever actions, shot guns for a very long time. There are risks in using a half cock safety, one of which the user cannot see if the sear is in the half cock notch. The sear might be balancing on the tip of the half cock, and a slight trigger pull would result in the hammer falling. And many accidental discharges resulted from the hammer slipping out from under the thumb of the user. And of course, unless the user has X Ray vision, the user cannot see if the half cock nose is broken or worn and neither the sear. Sears do break, and the 1911 goes full auto when it does.
The earliest accidental discharge I have found is in the 1917 National Match section of the Arms and Man magazine. In his tent, a civilian was lowering the hammer of his 1911 and the hammer slipped, the pistol discharged, and 200 yards away a Major had to be taken to hospital. Enough accidental discharges happened when lowering the hammer on a live round, that the Army decided that the carry condition was round in the chamber, safety on, pistol in the holster. However, post WW2 the carry condition changed. Vietnam veterans I have talked to said the carry condition was nothing in the chamber, hammer down, magazine in the gun. I wondered about this, and then I got to talk to a Kimber employee at a National Match. He claimed that 1200 Jeep transmissions had developed 45 caliber holes in their transoms, from 1940 to 1970. What happened was that officer's took their web belt and holster off, placed it on the floor, or between the seats, and then during Mr Toad's wild ride, (which happens more frequently than the military want's to admit) the holster got flung against the transmission transom hump, and firing pin inertia caused a discharge. Not having a round in the chamber would stop that from happening.
Vietnam veterans said what happened out in Indian country was between the Grunt and his Unit Commander. But back in cantonment, regulations applied. Incidentally, bases learned to take away all firearms, grenades, mortar shells, smoke grenades, etc from enlisted men when they came out of the field. Grunts did crazy stupid stuff with munitions and guns when they were drunk or high.
The Navy never allowed round in the chamber at all from the earliest Blue Jacket Manual I have found, which is from 1917. The only time the user put a round in the chamber was during a combat situation. You can imagine bullets ricocheting inside a cramped steel ship might cause a big problem.
