Our test guns represented the four types of trigger mechanisms used on police pistols today. (Clockwise from top left) Single Action—Browning HiPower; Double Action Only—Ruger KP95DAO; Double Action/Single Action—SiG P226; Safe Action—Glock 17.
Between 1900 and 1985 an officer or department looking for a service handgun had a very easy time of it. Their choices consisted of a Colt, Smith & Wesson, or Ruger double-action revolver chambered for the .38 Special or .357 Magnum cartridge. And while some officers dared to suggest issuing semiauto pistols as duty guns, such radical notions were generally ignored.
But things got considerably more complex in the latter part of the 1980s. That's when American police agencies switched en masse to semiauto pistols. And that meant that agencies had to decide not just between 9mm, 10mm, .40, and .45, but also between a number of different trigger systems.
In general, before 1929 all semiauto pistols were operated with a single-action trigger mechanism. Even though these guns had some form of external safety, they were designed to be carried with an empty chamber and a round was only chambered prior to the handgun being fired. This made them less than suitable as everyday police weapons.
In 1929, Walther introduced the first practical semiauto pistol with a selective double-action/single-action trigger. This mechanism allows the first shot to be fired by a long, double-action revolver-like trigger stroke while subsequent shots are fired with a lighter single-action pull. Walther was onto something mechanically, but its lackluster .32 and .380 pistols were not popular with police on this side of the Big Pond, and, in the United States, the revolver remained the king of law enforcement sidearms.
This began to change in the early 1950s when S&W introduced its Model 39. The Model 39 was not only the first American-made pistol with a Walther-like double-action/single-action trigger system; it was also the first US-made pistol chambered for the 9mm Parabellum cartridge. Throughout the '50s, '60s, and '70s, the popularity of these pistols with military, police, and civilian shooters grew steadily and soon every major manufacturer was offering one. Double-action/single-action pistols were the original choice of most American police when they began switching to self-loading pistols. But just when the place of the double-action/single-action pistol seemed secure, a new trend arose: the striker fired "Safe Action" pistol.
The "Safe Action" pistol owes its popularity to Gaston Glock. While his revolutionary Glock 17 was most notable for its use of a polymer frame, the pistol's success was due far more to its trigger than its frame material. Firing the Safe Action pistol requires a stroke that is shorter than the traditional double-action but longer and heavier than that of a single-action pistol. Glock's multiple passive safeties also eliminated the necessity for external safety levers and provided a much simplified manual of arms. This made it much easier to train new shooters, and it was perfect for American police agencies transitioning from revolvers to semiautos. Today, most major pistol makers offer guns that use variations of the Safe Action trigger mechanism.
Now, nearly 20 years after the development of the Safe Action pistol, the latest trend in semiautos is the double-action-only trigger mechanism. This type of mechanism requires a long, revolver-like trigger pull to fire each shot, and proponents feel it is the most practical-and liability-free-type of trigger for police duty pistols.
As with DA/SA pistols, the SiG P226 uses a long trigger stroke to fire the first round while subsequent shots are fired with a shorter, single action stroke. Note the external hammer and the hammer drop/safety lever located above the grip panel in front of the slide stop lever.
It's no secret to anyone who reads firearms publications that each of these trigger mechanisms has a loyal group of supporters and that their partisanship is not only vocal but, at times, has been known to verge upon fanaticism. Each claims that its favored type of trigger is the "most practical" or "safest" for law enforcement purposes. So let's look at some of the pros and cons of each trigger action.
Single Action (SA)-allows the operator to carry the pistol in one of two modes: hammer down on an empty chamber or "cocked and locked." While the former is not conducive to getting the pistol into action quickly, fans of SA pistols claim the multiple manual and (in some cases) passive safeties make these guns as safe as their counterparts, while the short trigger stroke permits very accurate shooting. SA detractors counter that the light trigger pull increases the likelihood of an accidental discharge, and this is why many law enforcement agencies limit the use of SA pistols to highly trained tactical or SWAT units.
Double Action/Single Action (SA/DA)-allows the hammer to be carried down on a loaded chamber and the first shot to be fired by a long, double-action trigger pull while subsequent shots can be fired in single-action mode. All are fitted with some type of lever that lowers the hammer on a loaded chamber and doubles as a manual safety. This trigger mechanism is very popular with police agencies who believe that the long double-action trigger stroke lessens the chance of accidental discharge. However, advocates for other types of trigger actions complain that transitioning from a heavy DA to light SA trigger causes the first-and perhaps most important-shots to be inaccurate. They also dislike the fact that the safety/decocker lever is usually mounted on the slide and difficult to operate without moving the gun around in your hand.
Safe Action- is a striker-fired system that is partially cocked when the pistol's slide goes forward. A longish trigger stroke pulls the striker all the way to the rear and then releases it to fire the cartridge. Safe Action-type pistols usually feature several passive safeties that are disengaged as the trigger is pulled through its full stroke. Fans of Safe Action pistols claim that the simplicity of operation of these weapons, combined with their multiple safeties, make them the easiest to learn to operate safely and competently. Detractors feel that the resulting "mushy" trigger pull precludes accurate shooting and the lack of a manual safety lever is a disadvantage if the officer's gun is snatched away.