DA/SA vs SA

[LWYM425]

Guys help me sort this out. An autoloader requires the hammer be pulled back on the first shot, but the action there after cocks the hammer for subsequent shots. This gun is DA/SA? If so how does a SA semi-auto work?

Also when you load a magazine, and chamber a round doesn't that automatically cock the hammer?

thank you

 

[Husker_Fan]

What you descibed is SA like a 1911 or Hi Power. With the hammer down, nothing happens if you pull the trigger.

Examples of DA/SA are some Berettas, Sigs, and S&W's (not the M&Ps). With the hammer down on a loaded chamber, pulling the trigger moves the hammer back until it falls on the firing pin. The slide then recoils back to eject the casing and cock the hammer for the next shot.

 

[Deanimator]

SA = An M1911, Browning Hi Power, Tokarev, etc. The hammer must be retracted to the cocked position for the first shot. This will happen automatically when the slide is retracted to chamber the first round. The hammer can however be carefully lowered, after which it must be cocked to fire the firearm. This is not recommended on a typical handgun such as a Hi Power or M1911. An original Tokarev has no manual safety and would typically be carried with the hammer down on a loaded chamber.

SA/DA = A S&W Model 39, SIG P220, Walther P-38, etc. Once the chamber is loaded by retracting the slide, the hammer can be lowered safely using a decocking/safety lever of some sort. When the gun needs to be fired, pulling the trigger will retract the hammer and allow it to fall, causing a round to be fired and the hammer again cocked by the action of the slide. If desired instead, the hammer can be manually cocked with the thumb. There are a few DA/SA handguns, such as the CZ75 which can also be carried cocked and locked (hammer cocked, safety on) like an M1911.

DAO = The hammer can be cocked ONLY by action of the trigger. When the slide goes forward after ejecting an empty case and chambering a new round, the hammer returns to the lowered position. The trigger action is exactly the same from shot to shot, retracting and allowing to fall, the hammer. A hammerless striker fired pistol can have the same sort of trigger mechanism which retracts and releases the firing pin itself with each pull of the trigger.

 

[dovedescending]

Which guns are DAO Striker fired? The trigger on my brother's pt145 behaves differently when the chamber is empty, as if it was pulling the striker back and ten releasing it, but in order to load the gun, you must rack the slide, which changes it to what feels like SA.

 

[DannyZRC]

DA handguns have a mechanism which connects the trigger to the hammer and allows the weapon to be "trigger cocked".

an SAO gun, like an M1911, cannot be cocked by the trigger and must be cocked either by the slide or by the operator's thumb.

 

[wild cat mccane]

A DA/SA use a decocker.

P99 for example. When you load it and pull or release the slide it is single. You must use the decocker, or drop the hammer by holding it and resting the hammer for it to be in DA. it now requires a full DA pull, but the next shot puts the hammer (or striker in the case of the P99) back into SA.

Taurus and the P99 have double strike where as most don't.

This means a failed fire will not require a manual reracking of the slide. Why DAO triggers like the Glock don't have restrike capability is confusing at best. Its not going to damage the 'fantastic' pull of a glock to begin with

Personally I find DA/SA best for carry. Long pull the first time (if you want, not required) and then you get SA. P99 doesn't have manual safety and has a 10-12lb double action that is smooth. Can't get better than that for a ready to use, yet safe trigger.

 

[LWYM425]

Deanimator, the M1911;

could I carry this with a round chambered hammer down and either manually cock the hammer when i'm ready to fire AS WELL AS pull the trigger to bring the hammer back (like a DA revolver?). All this in addition to hammer back on a chambered round but locked with the safety (as you mentioned).

CZ75 and M1911 are the only guns that can do that?

 

[Deanimator]

Which guns are DAO Striker fired?

I think the 9mm Browning Long LeFrancais was.

There's no reason why one CAN'T be.

 

[Shawn Dodson]

An autoloader requires the hammer be pulled back on the first shot, but the action there after cocks the hammer for subsequent shots. This gun is DA/SA?

No. By "pulled back" I assume you mean that the hammer needs to be manually cocked to fire the first shot. This describes a Single-Action (SA) trigger mechanism. It performs a single function - releasing the hammer. When the first shot is fired the slide automatically cocks the hammer. (On an SA pistol, if the hammer is not cocked then pressing the trigger causes absolutely nothing to happen.)

Whereas a pistol with a Double-Action (DA) trigger mechanism can be operated in DA or SA mode. In DA mode, pressing the trigger 1) cocks the hammer, and 2) drops the hammer. In SA mode the hammer can be manually cocked or automatically cocked when the cycles. In the last 20 years or so it has become fashionable to describe a DA pistol as "DA/SA".

Also when you load a magazine, and chamber a round doesn't that automatically cock the hammer?

Yes. With an SA pistol it's common practice to leave the hammer cocked and engage the manual safety (cocked & locked). DA pistols have a variety manual safety and/or decocker designs. For example a DA Taurus PT92 can be carried cocked & locked, but most DA pistols have either a hammer drop safety or a decocker. A hammer drop safety decocks the hammer and engages the manual safety when it is operated. A decocker simply decocks the hammer - it has no manual safety.

 

[Shawn Dodson]

This means a failed fire will not require a manual reracking of the slide. Why DAO triggers like the Glock don't have restrike capability is confusing at best.

A stoppage can be caused by more problems than just a faulty cartridge, for example:

1. Failure to feed
2. Unseated magazine
3. Failure to eject

This is why "Tap, Roll & Rack" is the immediate action to perform whenever you press the trigger and the pistol fails to fire. Pressing the trigger a second time does nothing to get the pistol running. With training, Tap, Roll & Rack can be performed very quickly. If Tap, Roll & Rack fail to get the gun running then you have either shot the gun dry and need to perform a Combat Reload or you've experienced a double-feed that needs to be cleared.

 

[The Lone Haranguer]

SA guns have to have the hammer cocked manually before firing. Usually you will jack the slide (which leaves the hammer cocked) to chamber a round, then apply the thumb safety, a condition known as "cocked and locked." With a DA gun, pulling the trigger both cocks and releases the hammer, hence the term "double action."

 

[Zerodefect]

SA/DA- trigger is revolver like on first pull, SA on every pull after until hammer is decoked. Must be decocked before reholstering, must cover hammer with thumb while reholstering to feel if it moves while reholstering.
A bit of an odd older stlye of CCW. I don't recommend DA/SA guns anymore.

Striker fired safe action allmost DAO guns- Glock, M&P, XD, Kahr, Walther PPS- simple pull trigger to shoot, don't pull trigger not to shoot. Simple operation makes them great for CCW. Just take your time reholstering them.

Many folks that carry a rifle for a living still prefere secondary guns with safeties because they can reholster them quicker than a Glock when the get the oportunity to transition back to their primary rifle. I just grab my shirt when I reholster and be careful. I prefere Glocks.


Restrike capability is useless. If the round didn't fire on the first hit, don't waste time striking it again. Besides, If my gun deosn't go boom, I don't know why it didn't go boom, but I do know that it did not. So I go straight into:

Roll (look for double feed)
Tap magazine in HARD,
Rack (with support hand over top thumb and index finger mostly with thumb pointing towards chest)
Bang

If its double feeded when you roll/look do this instead:
lock slide back
rip out magazine
knock out one round with finger if it deosnt fall out on its own
cycle slide to get chambered round out, sure it probally fell out but i cycle once or twice.
Reload
rack bang

Sounds like alot but you can do the above in a few seconds with practice, if you tap rack bang a double feed you'll be in a world of hurt. So allways roll look first. The above works for tactical rifle as well usually.

 

[Mike J]

There is a pretty good break down on trigger types here-www.thehighroad.org/showthread.php?t=248556
It probably explains it better than I could.

 

[REAPER4206969]

http://www.youtube.com/watch?v=HPQVNj-YHWs&playnext_from=TL&videos=L7WbMKA704I