The 1911 allows me to safely lower the hammer using only the hand holding the gun. But you won't find instructions on how to do that in any manual that I've ever seen. Certainly not in the GI instructions, or the Colt factory owner's manual.
It is, however, covered in the 1910 patents.
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 do this required
the keeping of the thumb of the right hand
in a horizontal position on the left 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 of 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 a projecting nose 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 farther
than to its cocked position.
When the hammer
is drawn fully back it strikes the nose and,
by pressing the same downward, it
causes 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 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,
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Note that the "safety position" described by Browning must, by description, be the half cock position.
To wit:
And it became necessary to lower the hammer to the safety position without touching the firing pin.
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Of course, the addition of the manual safety made the half cock safety obsolete, but the captive half cock remained a part of the design until Colt turned it into a flat shelf in the Series 80s.