How to Check A Polymer80 Or Glock’s Firing Pin Strike

One of the challenges when you are working on a firearm is trying to figure out what is going on in spaces you can’t directly observe. The Polymer80 frames given an awesome platform to build a custom pistol but you have the challenge of wondering just how hard the firing pin will strike the primer. I know a bunch of you load a round and test fire but that is not an option where I live now so I had to figure out an alternative.

The internals of a Glock reflect pure genius on the part of Gaston Glock. How he figured it all out is beyond me and the best I can do it is look at the parts and the functioning and draw conclusions about what is going on. Obviously a lot has to happen to release the firing pin and have it travel forward with sufficient force to strike the primer and trigger ignition. All sorts of stuff can go wrong and cause a light strike that then results in erratic firing.

So, I was sitting and wondering how I could test the strike in my shop. I started thinking about what I could put down the barrel that would get hit by the pin and both move reflecting the degree of force and also get dented so I could see depth, etc. My answer? A 1/4″ hardwood dowel.

I buy these 1/4″ x 3′ hardwood dowels by the bundle from suppliers but even at a big box store, a 3′ dowel will run you $1-3 for a 3-4′ long piece. I’m talking the plain jane wood dowels you see with the hardware and parts aisle section – not premium oak, etc.

So, I take them to my bandsaw and cut off about a 6″ section in my bandsaw and then I sand the ends real quick to get rid of stray fibers.

Here’s a new 6″ test rod next to a Polymer80 G34.
Look at how it’s nice and clean – no dents and also no stray fibers/slivers that will catch on the barrel.

How To Test

First and foremost, visually inspect the pistol and don’t assume anything. Make absolutely sure the weapon is clear – that there is no ammunition in the chamber or a loaded magazine. Life is going to suck in the next part if you pull the trigger and the pistol is loaded so make sure it isn’t!!

Step one, cut yourself either a new dowel or trim the end of an existing one so you have a clean end.

Okay, hold the pistol vertical, drop the dowel down the barrel and pull the trigger. The dowel should to shoot up about 2-3 feet in the air depending on what springs you are using. The stronger the spring, the further the dowel will go.

Try this with some known good pistols first to get a feel for how far the dowel pops up. If a 1/4″x6″ dowel doesn’t even leave the barrel then you know you have a problem.

Here’s the dowel sticking out the end.

Now, the second part of the diagnostic is to look at the divot in the end. There should be a clear indent in the wood. Look at this next photo:

That dent was made by the firing pin hitting the wood and is from my PF940CL pistol that works great plus it’s also running a full power OEM Glock firing pin spring. It makes a much more pronounced dent that my G34 which is running a reduced weight Glockmeister firing pin spring.

This method has worked very well for me as I can repeatedly test fire with the dowel to diagnose light strikes without constantly needing to shoot live ammo.

You can see this one is short. I’m not worried about a precise length. Before I test or after I am done, I trim off the end so I have a nice fresh “face” for the pin to hit so I can see it. Bear in mind that a shorter dowel will be lighter and fly further. This dowel is at the end of it’s useful length and I’ll use it for something else now.

I hope this little trick helps you out as well.


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