I needed a better way to test the fire control groups of 9mm Polymer80, Glock and SIG pistols where I could not see what was going on in the slide – I could only go by sound and feel but I really wanted to get an idea of how firmly the firing pin or striker was hitting 9mm, .40 or 10mm primer. What I evolved over time was to cut a 5/16″ hard wood dowel down to about 5″ and sand the ends to get rid of any splinters. This is perfect for pistols with a barrel less than 5″ long simply because you can see and feel the dowel jump.
By the way, 5/16ths of an inch as a decimal is 0.3125″ and that comes out to 7.94mm – it’s loose enough to slide in and out easily. It would not fit in a pistol with a barrel diameter smaller than that.
To use the test rod, I slide it down the barrel of a cleared weapon and pull the trigger. I could see how far the dowel was launched and inspect the indent made in the end of the dowel to gauge how well the firing pin was hitting the primer. My SIG P365 can seriously launch one of these through the air and you see a big dent in the wood end. My Polymer80s with stock Glock trigger springs do the same and you can the dowel move far less when they are in the pistols with reduced springs.
If I want a careful look at where the firing pin is hitting the dowel, I simply cut off or sand the end so it smooth and then test the pistol.
This approach has helped me so much in terms of diagnosing what is going on with my pistols that I want to share it with you.
This is for one hardwood dowel and nothing else. Any photos showing pistols or other parts are for illustration only and are not included.
From a safety perspective, always make sure your pistol is unloaded before testing and *always* make sure the rod has been removed from the barrel prior to loading live ammunition. I can’t stress this enough – please be safe with your pistols. Never ever assume a pistol is empty or safe – always, always confirm it. Also, always wear eye protection – the rod can shoot out surprisingly fast!
9/14/2022 Best Review Ever – “I thought you might be full of sh*t but decided to try the rod because I couldn’t figure out what was going on. In just a few minutes of using the rod, I determined the firing pin spring was crap – I bought a non-name frame parts kit off ebay – I’ll stick to brand name parts going forward.” — Robert