IV. Comparative Firearm Information

B. Double Action v. Single Action v. Safe Action v. Squeeze Cocker

by Josh Grosse (jdg00@juts.ccc.amdahl.com)

Handgun cocking system terminology comes originally from revolver usage, and has been adapted to autoloading pistols. The systems are:

DAO is a DA handgun which does not work in SA mode, too, since DA implies SA capability.

Heckler & Koch, and Glock proprietary systems are also described.

If the handgun is not already cocked, during the trigger pull the mechanism cocks the hammer and turns the cylinder, before firing.

You must cock the hammer manually. Pulling the trigger will not cock the hammer.

You cannot cock the hammer manually. These are usually "hammerless" revolvers, where the hammer is an internal mechanism.

If the handgun is not already cocked, during the trigger pull the mechanism cocks the hammer before firing. Unlike a DA revolver, which remains hammer down after firing, in an autoloading DA the hammer will be re-cocked during the loading of the next round. Sometimes these are called DA/SA to distinguish them from DAO pistols.

The hammer must initially be manually cocked. The hammer will be re-cocked automatically during the loading of the next round.

The hammer can not be manually cocked, nor is it cocked by the loading mechanism. The trigger pull cocks the hammer each and every round. These pistols may have internal or external hammers.

Glock pistols have what the vendor calls a "Safe Action." The pistol is operated as if it is DAO. There is no hammer, external or internal. Instead, there is a firing-pin tang held by the triggering mechanism. The ready pistol is in a half-cocked state. Squeezing the trigger completes the cocking, then releases the tang. It's trigger pull is consistent, like DAO pistols, but the Glock's standard trigger has a much lighter pull, similar to SA pistols.

H& K P7 series pistols have a squeeze mechanism on the front of the grip, which cocks the hammer. They behave, therefore, like SA pistols in their trigger pull (light, consistent) but do not require the cocked and locked safety systems of SA autoloading pistols.

Your choice of cocking systems is a personal decision. Please talk to your NRA Safety Instructor, spend time with your firearm dealer, and learn about the various models before you make your decision.

Whatever you decide, remember that a DA system should not be selected to "safely" hold someone at gunpoint with your finger on the trigger. An accidental discharge is possible, and under stress, it may even be likely. Only place your finger inside the trigger guard once the decision to fire has been made.

Practice your safe handling procedures EACH AND EVERY TIME you pick up your firearm. You'll be safer, and people around you will be safer, too.