Half Cock Function Explanation/Clarification?

[The Raven]

Hello All,

Can someone explain to me the purpose of the half-cock position on a semi-auto? I have several small Berettas (.22 caliber 21a and a .32 caliber Model 70) that have this, but I am unclear as to it's true purpose. I used to think that it was better to have it in this position if you were carrying the gun with one in the chamber so that if the gun was dropped and the hammer was struck, it would not be able to fire. However, from what I can determine from reading the somewhat confusing Beretta manual, this is not the case. Also, I would like to know if the function/purpose is the same for all handguns that have a half-cock position.

FYI, neither one of these will be my carry gun when I get my plastic, this is just a curiosity question about my plinkers.

[Big Calhoun]

Warning: I am not an expert

With that out of the way, my understanding is that the half-cock position on most guns is actually a safety feature -- a drop catch. Basically, if the hammer falls as a result of a drop, it's prevented from fully striking the firing pin. I'm pretty sure there's more technical aspects, but that's the jist of it as I understand.

I have a few guns that have that feature. I know in the documentation of my Beretta 96, it says the half-cock is strictly a safety feature and the weapon shouldn't be left/stowed in that position. The documentation for my HK USP makes no such distinction so I tend to leave it half-cocked.

[Thane]

The "half-cock" position on an external hammer is, indeed, a safety feature. On the 1911, it's actually a secondary notch machined into the hammer. If the sear happens to slip (and the trigger is not being pulled), the sear will end up catching in the half-cock notch, stopping the motion of the hammer. It's designed to add one more barrier between the user and a true accidental discharge (as a result of parts failure). While the 1911 can be carried with the hammer at this position, that's not the primary function of it - the 1911 was designed to be carried with the hammer back, thumb safety on.

It's not limited to semi-autos, though, nor is it limited to this one safety feature.

Old single action revolvers had a half-cock notch. While it could also function as a "safety," that was not the main purpose of the notch, due to the design (it was far safer to carry the hammer completely down, with no round under the hammer). Rather, placing the hammer in the half-cock notch allowed the hammer to disengage from the cylinder mechanism, letting the cylinder be turned by hand for loading/unloading.

The familiar lever-action rifles from Marlin and Winchester, however, are intended to be carried with either an empty chamber or a hammer at half-cock over a loaded chamber. With the hammer at half-cock, the rifle would break before it would fire, but a simple drawing back of the hammer to full-cock readies the rifle to shoot (and is more quiet than working the action).

Then you look at the Winchester 1897, an external-hammer shotgun. Not only does placing the hammer at half-cock render the shotgun "safe," it also locks the action so that you can't accidentally yank on the slide and empty the chamber. With that hammer at half-cock, the hammer itself is the only part that can be moved (unless you hit the slide release). Once again, this is to allow a hunter to safely carry the shotgun "fully loaded," and only have to draw the hammer back to fire.

Hope this helps.

[jimlongley]

And there is good reason for the old saying "Going off half cocked."

[The Raven]

Thanks for the info. Very helpful. My father has a lever action Winchester 30-30. I will have to give it a closer look next time I see him.