Delvo, on Aug 18 2004, 05:42 PM, said:
Your terminology is losing me. I've never seen single/double action refer to non-revolvers, and the definition I was given for single-action before (you have to take another step after firing once before you can fire again) contradicts the definition I was given for semi-automatic (you can fire immediately after firing by just pulling the trigger again; equivalent to double-action revolvers).
Single/Double Action refers to the way the hammer and the trigger interact with each other, and it delves fairly deeply into the way things work on a firearm.
On a single action, you have to cock the hammer before you can pull the trigger. If you pull the trigger with the hammer down, nothing happens. Thus, the trigger performs a single action
. Single action triggers tend to be fairly light. In the case of a properly tuned 1911, the pull weight is something along the line of 5 pounds. For competition and raceguns, the pull is something like 2.5-3 lbs.
With a double action, the act of pulling the trigger pulls the hammer back before dropping it. In this case the trigger does two things, hence double action. You can operate a double action firearm in single action mode (in most cases)(ie, cocking before firing), but you can't operate a single action in double action mode. Trigger pull for double action tends to be in the realm of 12-15lbs for many semiautos and 15-20 lbs for revolvers.
This is fairly straightforward for revolvers, but it gets a bit more confusing for semiautos.
As a sidebar, a little on how revolvers and semiautos differ... On a revolver, the act of pulling the hammer back rotates the cylinder to the next space and locks it in place. This happens whether you pull the hammer back yourself, or you pull the trigger in double action. On a semiauto, the recoil from the fired shot pushes the slide back, cocks the hammer, ejects the spent casing, and as the slide goes forward, it strips and feeds the next round from the magazine into the chamber.
Semiautos are either single action, double/single action, or double action only.
Single action semiautos require the operator to pull the hammer back before the first shot. Every shot thereafter is single action. (Remember, the slide cocks the hammer on each shot)
Double/single actions do not require the hammer to be cocked on the first shot. The act of pulling the trigger both cocks the hammer and drops it. Every shot after the first is single action. Trick here is that the first trigger pull is going to be heavier, thus requiring more force than the subsequent shots.
Double Action Only pistols fire double action on every shot. Every trigger pull cocks the hammer and drops it. These cannot be used in single action mode.
And sure enough, this next bit hints that there's more to the definition of what makes a 1911 than that...
...because such a consistent performance record can't come from the safeties alone; the guns that built that reputation must have some other fundamental functional traits in common. Otherwise, there'd be plenty of bad guns as well, that happened to also have those two kinds of safety.
Okay, I see what you're getting at...
Note again my opening paragraph:
"1911" is a general descriptor for a semiautomatic handgun that follows a design by John Moses Browning for the US Pistol, Caliber .45, Model of 1911.
It isn't the *safeties* that make the 1911, it's the overall mechanism. The dual safeties happen to be two of the most visible and innovative (at the time) features of the design.
Or is it that practically all non-revolver pistols these days are 1911s anyway?
The 1911 is a fairly small niche in a wide variety of different designs...
Beretta 92/US M9
Smith and Wesson 3913LS
The only thing I see at the rear of the slide is indicated in blue here.
That's the hammer.
From the name "grip safety" I'm guessing that the other safety is squeezed in the hand during firing so that the gun shouldn't fire when it's not being fired in a hand.
That's exactly right. If the gun's not being held so as to depress the grip safety, the weapon won't fire.
That sounds like it would be the part indicated in red.
Forgive me, I'm colorblind, I assume you mean the lowest bracket?
If so, the answer would be yes.
But the most unusual thing in the picture is the thing I've indicated in green. What in the world could THAT oddity be? Or is it actuallly one of the safeties?
It's called a beavertail, and it's cast as part of the grip safety lever, but has nothing to do with the grip safety's function.
One of the downsides of the 1911's design is that when you're holding the gun high on the grip (like you're supposed to...), if you have large hands, when the slide comes back and cocks the hammer, the hammer will actually "bite" your hand in the meaty part between the thumb and the forefinger. The beavertail goes between your hand and the hammer, preventing this.
Edited by jon3831, 19 August 2004 - 01:22 AM.
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