Why do we need the Double action only gun?

[167]

I can't help but wonder if maybe the premise of the question is flawed. It implies an assumption that DAO is inferior to SA or SFA trigger systems. Maybe the question should be why do we need SA or SFA? What does SA and SFA accomplish that DAO doesn't?

Personally I find their isn't a hairs breadth of difference between the trigger systems. A good DAO trigger is just as shootable as a good SA or SFA trigger.

 

[Nushif]

A good DAO trigger is just as shootable as a good SA or SFA trigger.

Fact.

 

[General Geoff]

I can't help but wonder if maybe the premise of the question is flawed. It implies an assumption that DAO is inferior to SA or SFA trigger systems. Maybe the question should be why do we need SA or SFA? What does SA and SFA accomplish that DAO doesn't?

All else being equal, a single action trigger can be made lighter and crisper than a double action only trigger. Yes, a DAO trigger can be made pretty darn light, but there will always be necessary travel or "creep" to it, in order to cock the hammer or striker. A single action trigger needs almost no travel to simply release the sear: 1mm or less.

Keep in mind that the overwhelming majority of rifles and shotguns have single action triggers. There are many more double action triggers found on handguns because of their more perceived likelihood to be accidentally or negligently fired by those with poor trigger discipline, or even curious children, and perhaps also because handguns are more often kept fully loaded, round chambered, than rifles.

Single action = better accuracy due to lighter/crisper trigger pull.
Double action = safer due to internal mechanism operation *and* possibly heavier/longer trigger pull

 

[167]

Single action = better accuracy due to lighter/crisper trigger pull.

I would disagree. Accuracy is not a function of the trigger, but a function of the shooter.

We could say that it might be easier for certain shooters to attain that level of accuracy with an SA trigger, but that is a fault of theirs, not the trigger system.

 

[General Geoff]

I would disagree. Accuracy is not a function of the trigger, but a function of the shooter.

Given that the trigger finger is part of the hand, and that the hand is what grips and holds a handgun steady while pulling the trigger and while the gun fires, logic dictates that the lightest trigger pull will be most accurate from a purely mechanical point of view. The heavier the trigger pull, the more the rest of the hand deforms around the grip of the gun as it's pushed more into the palm and thumb/index finger web from the trigger being pulled by the index finger. You could have the strongest fingers in the world, but the flesh is still not a perfectly hard surface, and a heavier trigger pull does equate to more deviance of gun position between rest and firing. Granted this mechanics-level accuracy difference is extremely small and probably unnoticed with most handguns.

The more realistic reason for SA triggers being more accurate is the tensing of non-finger hand muscles and more noticeable changing of the hand/grip position while firing the pistol. This can be mostly overcome with enough practice and trigger finger strength.

Accuracy is a function of the shooter, the gun, and the ammunition in concert. The shooter makes most (~95%) of the difference at typical pistol shooting distances, but the ergonomics of the gun can vastly change the accuracy of a less-than-perfect shooter. This is why it is imperative for people to purchase, carry and practice with guns that they shoot well, not necessarily what their buddy/coworker/spouse shoots well.

 

[Apocalypse-Now]

I like to know what kind of advantage DAO has ?

it meets the needs of PD's in PC democratic states/counties.