Although the Glock (and its emulative systems such as the M&P and CZ P-10) tend to be the dominant pistols in the market, I am aware that not everyone selects or prefers it. I recently had a consulting contract where the shooters were using the SIG P226 (don't ask). And I have seen more and more police special units select that type of weapon, notably the CZ-75 and CZ P07. Is the DA pistol making a comeback? Maybe. Let's examine why that might be. And no...I am not going to sell all my Glocks. You are the weapon...your pistol is only a tool. And nobody says you can't have several tools.
My first police semi-auto was a SIG P-226 way back in 1988. I shot Distinguished Expert with it and carried it for years. Later when the 3rd generation S&W was selected by the agency I worked with, I used that. It was like a rough Beretta 92. I took that weapon to Gunsite in 1990 and not only shot the top score in the class but won the shoot off against an entire relay of LAPD SWAT with their 1911s and several LAPD HITS instructors with their 92Fs. One could say I know a few things about the DA/SA trigger system.
Advantages and Disadvantages of the Double Action Pistol:
The Double Action pistol's trigger is its heart and an advantage to those who learn to use it (and a disadvantage to those who do not understand the system).
1). HOLSTER-LESS CARRY
The DA Pistol allows for holster-less carry in situations where a holster may be contraindicated (such as a place where it might be socially unacceptable to carry a weapon, but tactically necessary to do so).
Why is holster-less carry important at such times? Those of you who have carried in those places will know that there are times when you may need to divest yourself of your weapons preemptively, such as when you are about to be searched, or when about to be contacted by an authority figure. An empty holster, once discovered, will get you unwanted attention. Whereas a found pistol may be easily discounted if it is not on your person. Yes...this is more for the "dark arts" - undercover type guys than the "good citizen" types, but there it is.
There is a time for holster-less carry, and that is impossible with a striker fired pistol.
2). GREATER SAFETY UNDER DURESS
The inherent safety of the long trigger allows for leaving the weapon in situ, on a nightstand or desk, without concern. And if grabbing up that DA pistol in the middle of the night to answer that "bump" in a sleepy stupor, a wandering trigger finger would not potentially betray your intentions like a short/light striker type trigger might.
Never say never. No matter how good your trigger discipline is, the DA Pistol is a little more Murphy-proof.
3). AMAZING SINGLE ACTION TRIGGER
While trouble with the long-and-heavy double action trigger is greatly overstated, and is easily mitigated by training and by technical means, the polished and tuned single action trigger on these pistols can be made amazingly crisp and light making the hyper-accurate shot easier. Such single action triggers are often better than what is safely possible with a striker fired pistol, and comparable with a tuned 1911 trigger. In fact, the tuned and light SA trigger on a properly arranged SIG P-226 would be considered completely unsafe on a Glock or SIG P320.
Now I am discussing the triggers seen on the traditional Double Action systems. A Glock and a SIG P-320 are not DA pistols regardless of what the company parrot in the factory sales shirt tells you. They are in essence striker fired single action pistols if we must categorize them, but they are not what we are discussing here.
And the various DAO (double action only...like a magazine fed revolver), and DAK and various other variations that seek to eliminate the single action portion of the trigger are not the same either. Yes, I know that a man can get used to them, but they offer no advantage to the traditional DA/SA. Their sole purpose in design, execution, and marketing is to allay the fears that a cocked pistol with the hammer back creates in the minds of some people. The guys will benefit from these are the non-dedicated personnel who forget to decock the hammer prior to holstering, and the poor administrators that must manage such people. Even the best and lightest DAO trigger (perhaps the one found on the HK system) is not anywhere near as short and light as a tuned single action trigger. And remember that trigger movement and weight (less is better within reason) will affect your ability to hold on target while the hyper-accurate proactive shot is fired.
4). MULTIPLE ADAPTABLE TRIGGER ACTIONS
These pistols normally are called "Double Action", referring to the double action of cocking and firing, and subsequent action of firing with a cocked hammer. Some trainers that specialize in these have even gone to the point of cutting off hammer spurs on their pistols to preclude any other way to run the weapons (a mistake in my opinion). The way I use these pistols, and train others in their use is that the trigger actually has four modes of use.
The double action first shot. This is the reactive shot at close range on a large and forgiving target. It is just as fast as any single action of striker fired pistol. A reasonable DA trigger weight is about 10 pounds, although lighter is fine as long as reliability is not compromised. I have seen DA triggers as light as 7 pounds and totally reliable.
The single action second shot. Detractors of the system make a great deal of noise about the dreaded transition from DA to SA. In truth, it is not an issue at all unless you set out to make it an issue. Once you learn the trigger reset, that dreaded transition becomes as mindless as shifting gears on a manual transmission. A good tuned SA trigger can be 2.5 - 3 pounds.
That is where most users of this system leave things but there are two additional methods for trigger use.
The single action first shot. When the DA shooter has time, such as will be evident in a proactive shot, or a distant shot, or in a planned contact, he can thumb cock the hammer on the draw very easily and go single action from the beginning. That some trainers break out into hives at the mere thought of doing this tells me they do not understand the system.
The staged double action shot. For intermediate distant targets that are contacted in double action mode, the shooter may begin in double action and allow the hammer to stall on its rearward arc, or "stage" as the last sight and alignment verification takes place prior to firing the shot. This in essence turns double action into single action without touching the hammer and some of the great DA shooters actually do this for long or difficult shots without realizing it.
The double action pistol is not as simple a system as a striker fired weapon, but that does not make it less worthy of consideration. Think of the DA/SA pistol's role like that of the manual transmission compared to an automatic transmission. A manual transmission driver has to work a little harder and be a little more in tune with his vehicle, but if he drives it well, he realizes many advantages over an automatic transmission.