Glock striker parts: firing pin, spring, cups and spacer

The striker is the part of a Glock that actually fires the round, and its assembly is the part most owners have never taken apart. Five small pieces live in the back of the slide, and each one has a job in the pull and the strike. This guide names them, explains what each does, covers the differences between generations, weighs the aftermarket options and tells you how to take the assembly apart and put it back without launching a spring across the room.

The parts

Firing pin, or striker: a steel rod with a tip that hits the primer and a lug at the rear that the trigger bar's cruciform catches.
Firing pin spring: the coil around the striker that drives it forward when released.
Spring cups: two half-cups that hold the rear of the spring against a collar on the striker.
Spacer sleeve: a polymer tube behind the spring cups that centers the assembly and is what you push down to remove the slide cover plate.
Firing pin channel liner: a plastic tube pressed into the slide that the striker rides in.
Firing pin safety and spring: the plunger in the slide that blocks the striker until the trigger bar lifts it.
Slide cover plate: the polymer plate that keeps everything in the slide.

How it works

At rest the striker is partly cocked, held by the cruciform. The pull finishes cocking it, lifts the safety plunger and releases the lug; the spring, compressed between the collar at the front of the striker and the cups at the rear, drives the tip into the primer. When the slide cycles, the striker is pushed back and caught again. The plunger's job is to block the striker whenever the trigger is not being pulled, so a dropped pistol cannot fire; the cruciform's is to hold the striker back. Both must work for the pistol to be drop safe, which is why the plunger spring stays factory.

Generation differences

Gen 1 through Gen 4 share one striker, spring, cups, sleeve and firing pin safety in each caliber; the 9mm and .40 strikers differ in tip, and the .45 and 10mm large frames use their own. Gen 5 changed the striker, the firing pin safety and its cut in the striker, and the spring cups, and the Gen 5 parts do not fit earlier slides or the reverse. The slimline 43, 43X and 48 use a smaller striker assembly of their own. The channel liner and cover plate are common across the standard-frame generations. Buy striker parts by model and generation; every listing here states them.

The striker spring

The factory spring is rated about 5.5 pounds. It is the spring you compress during the pull, so a lighter spring lightens the trigger and weakens the strike; a heavier one does the reverse. Reduced-power springs of 4.5 or 4 pounds are the second most common match change after the connector and the most common cause of light strikes with hard primers. Extra-power 6 pound springs cure light strikes in a pistol that has them and add a little pull. Springs wear slowly; replace the striker spring every few years or when a pistol that used to fire everything starts leaving light dents in primers.

Aftermarket strikers

Lightweight titanium or aluminum strikers reduce lock time, the delay between break and strike, which competition shooters value, and they need the full-power spring to hit hard enough. Extended-tip strikers reach a few thousandths farther and cure light strikes on some ammunition. Stainless strikers resist rust in the channel. A skeletonized or lightened striker on a reduced spring is a match-only combination. For a carry pistol, the factory striker and spring are the answer; nothing on the market improves the reliability Glock ships.

Channel liner and cleanliness

The channel liner is pressed in at the factory and does not come out for cleaning. The channel itself must be kept dry: oil in the striker channel collects unburned powder and, in cold weather, thickens enough to slow the striker and cause light strikes. Clean the channel with a dry patch on a rod when you have the striker out and never oil it. Replace a liner only if it is damaged, if the slide has been through a fire or if an aftermarket slide came without one; a liner tool presses the new one in.

Taking it apart

Unload, check the chamber twice, field strip. Hold the slide muzzle down, press the spacer sleeve down with a punch and slide the cover plate off while keeping a thumb over the opening; the striker and the extractor depressor plunger will try to leave. Lift out the striker assembly. To change the spring, hold the striker, compress the spring against the cups with a tool or a small Glock spring tool, slide the two cups off sideways and release the spring slowly; wear eye protection, the cups fly. Fit the new spring, compress, refit both cups so they seat against the collar, and check the assembly is straight. Reverse to reassemble, pressing the sleeve and the depressor plunger down as the cover plate slides on.

Checks after

With the slide off the frame, push the striker forward from the rear: the tip must not protrude from the breech face until you depress the firing pin safety plunger. Release it and confirm the plunger springs back up flush. Then reassemble the pistol and run the function checks, including the slam test with an empty chamber. Fire 100 rounds, including your carry load, before trusting a new spring or striker.

Browse Glock strikers and firing pin parts and springs, see the whole system in how a Glock trigger works, and find every spring in the pistol in the spring kits guide.

General information, not legal advice. Current as of September 2026. Laws change; check the official source before you act.