Odd Results In Glock Firing Pin Shake Test

[Radiator]

I was talking to a friend that went through the Glock armorer's course recently. We started talking about the firing pin shake test. Here's how to test whether the firing pin travels freely.

Drop the magazine, clear the chamber. Pull the trigger and keep pressure on trigger. Shake the pistol forward and backwards. Listen to see if firing pin moves freely.

All of my Glocks have firing pins that float around when you put pressure on the trigger. But, three of them have firing pins that have full travel without putting pressure on the trigger. The other four don't make a sound unless you do keep pressure on the trigger.

I'm trying to figure out what's different in the pistols that have firing pins that float all the time versus the four that act "normal."

Any ideas?

Bill

[RandySmith]

The firing pin safety is most likely binding with the firing pin on the ones that don't 'rattle' without pressure on the already rearward trigger.

Randy

[Radiator]

Yes, Randy, I think the firing pin safety is touching the pin. Overall I don't think this is a problem. All my Glocks do pass the test as stated in the armorers manual. I'll have to bring one of them to a GSSF match and have an official armorer look at it.

Bill

[Bronson7]

Hmmmm. Someone please educate me here. Shouldn't that test be performed WITHOUT applying rearward pressure? The way it's done (according to the armorers class) would seem to indicate a striker/FPS/Trigger bar interference (most likely caused by the trigger bar). This sounds more like a test to check for striker/FPS/trigger bar interference and not for a properly functioning striker/FPS/trigger bar interface. Something I'm not getting here.
Bronson7

[Kal El in SLO]

In the armorer's class you are taught to first shake the gun with the trigger in the fully forward position. There should be a little rattle from the firing pin contacting the firing pin safety.

Next, the trigger should be pulled and held to the rear of the gun. While still holding the trigger, shake the gun. Now you should be able to hear the firing pin moving freely.

If you are worried about your firing pin safety not functioning properly....you need to take your slide off the receiver and try to manually push the firing pin through the firing pin safety by applying pressure to the firing pin lug. If your gun fails this test....DO NOT USE IT. You will most likely have to change the firing pin and/or the firing pin safety.