How to Disassemble a Glock 21

How to Disassemble a Glock 21

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The Glock 21 is a semi-automatic pistol chambered for the large .45 ACP bullet. The pistol features the safe-action system, a series of three safeties that release as the trigger is pulled and immediately reset afterward. Glock handguns feature polymer lower receivers and a double-action style trigger pull (requiring greater pressure to fire the weapon). Glock handguns are a very popular with military and police agencies worldwide because of their durability, light weight and reliability. Another great advantage of a Glock is its simplicity; the pistol requires no special tools to disassemble.

Point the pistol in a safe direction and (with your finger away from the trigger) press the magazine release located on the left side of the pistol directly next to the trigger guard. Remove the magazine.

Keep the pistol pointed in a safe direction and pull back the slide with your non-shooting hand. When the slide is completely back, push up the slide-stop lever (located just above and slightly behind the trigger guard), this will lock the slide in the rear position. Inspect the pistol's chamber and verify that the weapon is unloaded.

Pull back on the slide (releasing the slide-stop lever) and allow the slide to travel forward.

Grasp the slide with one hand (over its top) and place your other hand on both slide-locks (the levers located on each side of lower receiver just above the trigger guard).

Pull the receiver back approximately 1/10 of an inch and simultaneously pull down on the slide locks. Keep the slide-locks down and push the slide forward until it separates from the lower receiver.

Set down the lower receiver and turn the slide over.

Remove the spring assembly by lifting off the small step on the back of the barrel. No further dis-assembly is required on the spring assembly.

Lift the barrel from the back and slide it out of the slide assembly.


  • Always check that your weapon is unloaded before disassembling. Steps one and two relate to clearing the weapon.


  • Exercise extreme caution when removing the spring assembly. The spring is under tension and can cause injury if accidentally released.
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