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Handguns

Charter Arms revolver
Charter Arms revolver
Courtesy of Forensic Technology Inc. Gunsights Pro 3.0 (see reuse policy).

The term handgun refers to all firearms designed to be capable of firing with one hand. There are two general types of handguns - revolvers and pistols.

Revolvers are handguns with a cylinder containing several chambers arranged to rotate around an axis and discharge successively using the same firing mechanism. The number of chambers ranges between five and nine, typically six.

   

The most common revolver types are

  • single action,
  • double action.
Gold cut trophy pistol
Gold cut trophy pistol
Courtesy of Forensic Technology Inc. Gunsights Pro 3.0 (see reuse policy).

Pistols are handguns with a chamber that is an integral part of the barrel. Pistols do not have rotating cylinders.

There are three types of pistol:

  • Semiautomatic
  • Full automatic
  • Single- and multibarreled

Semi- and full automatic are by design autoloading firearms.

 

Single-Action Revolvers

Single-action Ruger revolver .357
Single-action Ruger revolver .357
Courtesy of Forensic Technology, Inc. (see reuse policy).

Single-action revolvers require manual cocking of the hammer before sufficient force on the trigger releases the firing mechanism. When the hammer is pulled to the rear (cocking) an internal hand or pawl rotates the cylinder clockwise or counterclockwise, moving the next chamber into alignment with the barrel and firing pin. The hammer then locks into place along with the cylinder. Pulling the trigger releases the hammer, driving the firing pin to detonate the cartridge. Older models can be placed in a safe mode by pulling the hammer slightly to the rear; the hammer locks in place, keeping the firing pin from resting on an unfired cartridge case.

The cylinder of the single-action revolver is usually held in place by a removable pin; a loading gate is located on the right side of the firearm. By opening the loading gate and placing the hammer in an unlocked position, the cylinder can be rotated to ensure that all cylinders are empty. To the front of the chamber (located below the barrel), an ejection rod is used to eject fired cartridge cases from the cylinder. Some single-action revolvers do not have an ejection rod system and require the removal of the cylinder to remove the cartridge cases.

Modern Single-Action Revolvers

Ruger revolver transfer bar
Ruger revolver transfer bar
RCMP Firearms Reference Table (see reuse policy).

Modern single-action revolvers generally include an integrated safety feature to prevent accidental discharge. For example, Ruger revolvers use a transfer bar safety. This involves the use of a bar connected to the trigger. When the trigger is pulled, the bar is raised up to be struck by the falling hammer, transferring the energy of the hammer to the firing pin. Without the trigger being pulled, the hammer will not make contact with the firing pin.

 

   

Outline diagram of a single-action revolver handgun with hammer block highlighted and labeled.
Outline diagram of a single-action revolver handgun with hammer block highlighted and labeled.
Courtesy of AFTE (see reuse policy).

Some single-action revolvers use a hammer block safety which, in the safe position, blocks contact between the cartridge and the hammer. When the trigger is pulled, the bar is retracted and the hammer is allowed to make contact with the firing pin, striking the cartridge.

 

 

Double-Action Revolvers

Double-action revolver uncocked
Double-action revolver uncocked
Courtesy of St. Petersburg College Firing Range (see reuse policy).

Double-action revolvers are similar to single-action revolvers, with the following exceptions:

  • Function.
    • Double-action revolvers allow the hammer to be cocked and released with a single pull of the trigger.
      • Most double-action revolvers have the capability to function in either the double- or single-action mode. However, some models are designed to fire in the double-action mode only; the hammer cannot be manually cocked and the trigger must be pulled.
         
    • Used in the double-action mode, the cylinder is locked into place by the cylinder stop; the hammer does not lock into place since the cocking and releasing of the hammer is achieved in one motion.
      Cylinder stop
      cylinder stop
      Courtesy of St. Petersburg College Firing Range (see reuse policy).
    • Ejection/extraction.
      • In double-action revolvers, the cylinder release device is generally located on the left rear of the frame, whereas in single-action revolvers, the loading gate is located on the right.
        Cylinder release device
        Cylinder release device
        Courtesy of St. Petersburg College Firing Range (see reuse policy).
      • By manipulating the release device, the cylinder will unlock and swing out to the left of the firearm. The front of the cylinder has an ejection rod, which is used to eject all the fired cartridge cases or cartridges from the cylinder with one movement.
        Double-action cylinder ejector rod
        Double-action cylinder ejector rod
        Courtesy of St. Petersburg College Firing Range (see reuse policy).

    Modern double-action revolvers generally use the same accidental discharge prevention mechanisms as single-action revolvers the transfer bar or the hammer block.

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