Mechanics of a Gun: Types of Action

---

The way a gun functions more commonly referred to as its action will vary between guns. Deciding which type of action is best for you when carrying concealed is something to consider before buying your first gun for concealment of even one you only intend to use for shooting sports. 

Semi-Automatic

Semi-automatic guns are among the most widely used guns in existence. When the trigger is pressed one round is fired but these types of guns perform all actions needed to reload a new round and ready it (putting it in battery) for when the trigger is pressed again. The recoil spring inside the slide prevents the gun from firing again until the trigger is pressed. There are two types of recoils in semi-automatic guns: Gas operated which uses the gases that are generated from the bullet traveling down the barrel to pull the next round into battery and blow back where the actual recoil movement of the gun forces the next round into battery. Blow back operated guns have a harsher recoil than gas operated ones.  

Fully-Automatic

These types of guns do not have a recoil spring and will keep firing as long as the trigger is held. They are heavily regulated by the federal government dating back to the National Firearms Act of 1934, command high prices well into the thousands and tens of thousands and are not necessarily readily available due to a law that was passed in 1986 called the Hughs Act which prohibited civilians from owning full autos made after the law was signed.

Single Shot

Single shot guns are ones where the shooter must manually prepare the round to be fired such as in lever action and bolt action rifles or pump action shot guns. The lever, bolt or pump loads the round into the chamber for firing. 

Single Action Vs Double Action

There are two types of actions which refers to how the mechanisms that fire the gun operate:

Single Action Only (SAO): Single action guns are so called because when pressing the trigger, only one action is performed;; the external hammer drops forward allowing the firing pin to disturb the primer, igniting the gun powder to create the explosion that forces to the projectile down the barrel and out the muzzle. Therefore, the hammer must be cocked back before the gun can be fired. In a single action gun wracking a the slide seats a round and cocks the hammer back. 

There are three ways you can prepare this gun for carry. One is called cocked and locked meaning that there's a round in the chamber, the hammer is cocked back and the safety is engaged. Never carry this way without the safety engaged because the safety is the only thing stopping the hammer from dropping forward and striking the firing pin. Also be aware that when wracking the slide to seat a round in the chamber, the gun is ready to fire at that point and in most SAOs you cannot wrack the side with the safety engaged so be sure to engage the safety right after seating a round into battery. You can also carry with the magazine inserted in the magazine well but no round in the chamber. With no round in the chamber engaging the safety isn't necessary as the gun will not fire until a round is in battery but if you decide to engage the safety, keep in mind that you will need to complete two actions-disengaging the safety and wracking the slide-to put a round in battery before firing. This will increase the time before you can fire the gun in a crisis scenario. You can also carry with a round in the chamber but the hammer forward which requires you to ease the hammer forward after seating a round. Much caution is needed when doing this as you don't want the hammer to come forward with enough force to fire the gun. Carrying this way would require you to manually cock the hammer back with your thumb before the gun can be fired. I advise not carrying this way if you're not an experienced gun owner due to the need to ease the hammer forward after a round is seated. With an SAO gun, you must complete a least one action before firing the gun: wrack the slide to seat a round, disengage the safety or manually cock the hammer back no matter which way you decide to carry. 

Double Action Only (DAO): In a double action gun pressing the trigger does two actions hence the name double action - the hammer is cocked back and dropped forward. As a result double action guns don't need to have an external hammer. Many of them have internal firing mechanisms commonly referred to as striker fired guns. Some of these guns don't even have manual safeties but rather what is called a trigger block and/or a grip safety. While caution needs to be heeded whenever you carry or handle a firearm, carrying a gun of this action type would require less pre-firing action should you need the gun in a crisis situation such as disengaging the safety. 

There are also guns that are both single and double action (DA/SA). These guns typically have an external hammer. The first time the trigger is pulled the gun is in double action and the hammer is cocked back then drops forward. After the first round is fired, the hammer then stays cocked back after every press of the trigger and the gun is in single action until the magazine is empty and reloaded. 

What's Best For Concealed Carry?

Deciding which gun is best for concealed carry is a matter of preference. Single Action Only guns have a lighter trigger pull due to the trigger performing only one action but the pre-firing action might waste valuable time in a crisis scenario. Double action guns as stated above require less or no pre-firing action but have a heavier trigger pull.