Today’s handguns come in an amazing variety of configurations, especially when it comes to trigger mechanisms. Without getting too “techno-geek” on you, first there were the original “six-shooters” — familiar to anyone who’s ever seen a Western movie. The operator manually thumbs back the hammer, rotating the cylinder to bring the next round into position, then presses the trigger. Repeat.
Later came double-action revolvers, which could be fired either in single-action mode as described above, or in double-action mode, where a long trigger pull cocked the hammer, rotated the cylinder and then released the hammer.
Today, most defensive revolvers are either double action/single action or double action only (which usually feature an internal hammer). This is seen as a safety feature — requiring the generally heavier double-action trigger pull makes inadvertent firing less likely.
Today, anyone contemplating an auto-pistol for self-defense is confronted by a bewildering array of choices, especially when it comes to trigger mechanisms. And each design has its fans, and its critics. Here are a few.
Single Action Only
The most common example is the Model 1911, without a doubt the most famous handgun in history and still in wide use today, more than 100 years after it was invented by John M. Browning, the “Godfather” of modern auto-pistols. Once loaded and chambered, the hammer is either manually lowered (not recommended) or, more commonly, a manual safety is activated, allowing the gun to be carried hammer back, safety on, or “cocked and locked” — the preferred method.
Single Action/Double Action
Longtime and popular configuration. Once loaded, and a round chambered, some method of returning the weapon to a “safe” condition is employed, after which the gun can be fired in double-action mode, requiring a relatively heavy trigger pull on the first shot, with all subsequent shots in single action, with a significantly lighter trigger pull.
Berettas (and others) employ a “hammer drop” which causes the hammer to fall (without striking the firing pin). On the other hand, the SIG Sauer uses a true “de-cocker,” which slowly lowers the hammer to its resting position.
Double Action Only
Once loaded and chambered, a relatively long trigger pull is required on every shot, first to last. A number of manufacturers offer DAO versions of their Single-Action/Double-Action guns as an option (Beretta, H&K LEM, SIG Sauer DAK). Trigger pull weight is usually midway between a double-action trigger and their single-action triggers. Most of these guns allow a “second strike” (to deal with failure-to-fire) by simply pressing the trigger again, although with a much heavier pull.
It was Glock that brought this interesting engineering approach to handguns. Instead of a hammer (either internal or external), the design features a “striker” (essentially an extended, spring-loaded firing pin) that is pre-cocked upon racking the slide, then releases when the trigger is completely depressed. The trigger pull is typically very short, and the pressure required is relatively light. Most have no manual safety.
Today, Smith & Wesson (M&P), H&K, Springfield (XD), SIG Sauer, Ruger and many others offer striker-fired models.
Striker-Fired/Double Action Only
Relatively unique in function are Kahr pistols. While striker-fired, rather than the short trigger pull found on Glocks and others, they feature a long — but relatively smooth and light — trigger pull, every shot. However, like most striker-fired guns, they have no “second-strike” capability.
Bottom line? Try as many as possible, ideally at the range. And consider all aspects, especially safety, not just how well you shoot one over another. Then choose wisely!