Easy Firing Pin Fix

You broke your gun — What now?

Oopsie — broken shotgun firing pin is at the right. The other “good” pin is used as a reference.

During my decades of “hobby gunsmithing” — as I like to call it — I’ve lost count of the number of broken firing pins I’ve fixed, replaced, rebuilt or caused me to eventually throw my hands up in despair. While the most recent one has to do with an over/under shotgun, the same basic steps apply to just about any firing pin for revolver, auto, rifle, shotgun and even many .22s. The real mystery is when the pin is missing and you can’t find a sample, even in a picture — but that’s another story!

This is a friend’s gun and what happened was after firing, the pin didn’t retract fully so when he opened the action, it bent and broke off the firing pin’s tip. Initially he couldn’t figure it out, but just knew the pin seemed stuck “out” as he said. He tried to find a pin online with no luck. He told me about it and since I have some experience fixing shotgun firing pins, I figured I could just make one to lend a hand.
TakeDown TIPS

Here, the hammers are cocked and the rounded ends of the firing pins show just ahead of the hammers (red arrow).

TakeDown Tips

If you attempt something like this, use your “magic” smartphone and take plenty of pics while you disassemble things. To say they’re worth their weight in gold at such times is a serious understatement! “Oh, I’ll remember how the widget goes back on.” Nope. You won’t.

Once the gun was apart, I saw the issue. This is an affordable “big box store” shotgun so the final fit and finish of the parts wasn’t great. The pins showed plenty of peening and wear already, even though the gun wasn’t very old.

A firing pin needs to be soft enough to take repeated blows without shattering, but hard enough to withstand wear and tear. It’s a delicate balance at times. In this case, it looked like the peening on the broken pin had jammed it in the firing pin channel, causing it to stick out, hence the break. But, I saw this was an easy fix.

Roy makes the first pass on the cut-down screw to get the correct outer diameter.

Getting close: the unbroken pin is used as a guide. Roy uses a digital caliper,
along with his Mark I Eyeball, to make sure!

Big Nail Or Bolt?

Yup. Believe it or not, a nail or bolt often makes great raw stock for firing pins of all sorts. I might not use one for a .300 Win. Mag. but for old revolvers, many autos, shotguns, .22s and such, your spare parts bin is your bag-o-old-nails, bolts and screws! Since I didn’t have a big enough nail handy for this one, I used an old lag screw. Just keep in mind you don’t need or even want an extremely hard bolt. Regular Home Depot bulk-bun stuff like nails and bolts are fine.

I spent a bit of time with a digital caliper, drew up a simple chart for dimensions and turned the unthreaded end to proper diameter after hack-sawing off the bolt head. Then I carefully turned the other diameters of the various bits. When you turn the final pin end there’s not much strength there so very light cuts of .001, finished to size with a very light file, are the ticket.

Once finished on the lathe, I used my small mill for the cross-cut where the action/receiver pin crosses to hold the firing pin in its channel. It’s wider than the cross-pin since the firing pin needs to move forward and backward at the blow of the hammer. The spring holds it “retracted” and when the hammer strikes (inside the guns’ action) the pin flies forward, striking the primer, then the spring retracts it so the action can be opened. Unless the pin sticks and the end gets broken off!

(L-R) The broken pin, the unbroken pin and the “made from lag-screw” rough version.
Notice the peening and wear on the old pins due to soft steel.

The slot cut and a bit more work with a fine file tidied things up. It’s ready to install.

Final Stuff

A bit of light hand work in the lathe rounded sharp edges and a touch of 220 grit to 400 grit paper made things smooth. I love it when a project comes together and it worked fine right off the bat. I always learn something, enjoy this sort of work and doubly enjoy the big smiles on the faces of the people I help. And, it helps to keep my “sipping bourbon” stash well stocked! “Thanks Roy, here’s a present!”

Something to keep in mind is this is very simple to do. If you have an electric drill you have a “mini-lathe” and can use a file to shape things like this. You can also use a file to cut the slot. I’ve also found old ball-point pens can often supply springs needed, and just about everybody has a pile of rusty nails and bolts around. The key is “don’t get in over your head,” and make sure you match the original firing pin length or, if it’s worn, make yours a bit longer so you can shorten it to fit as needed.

Presto, good as new. Actually, at least one firing pin is better than new!

Just don’t blow yourself up!

Do you have an experience fixing a broken gun like this? Tell us about it and send a photo or two. We’d all love to see it. Also, go to www.brownells.com if you want to shop for gunsmith tools of all sorts!

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