≡ Menu

Reparing a small cannon firing mechanism.

Sometimes I get odd jobs coming into the shop. Recently the oddest project was a request to repair the firing mechanism for a signal cannon mounted on a yacht. Why not ? It’s a type of “gun” after all. The corrosion from the saltwater exposure and the lack of basic maintenance had rusted the firing pin in place. The owner appears to have tried to pound the firing pin loose with a hammer. This made things a little worse. So I decided to drill and ream the entire block and firing pin out. I used an end mill chucked into the tailstock to do this.

Next, it’s off to the milling machine to align the tap with the tool that I use to keep tension on the head of the tap and to keep everything in alignment.


Then I make a firing pin bushing.


The bushing gets a slot cut into the face for easier installation using a jig specifically for centering screw slots.


Oh yes, the firing pin itself. Now I thought about this for a bit. What better material for something that gets fired pretty often and takes a serious pounding ? Well how about a modified pin punch ? A trip to the local hardware store and I picked up a pin punch for a relatively inexpensive price. This is some metal that gets beat on a lot by hammers, so why not modify one into a heavy bodied firing pin ?


Here’s the newer heavier duty firing pin. Along side it are the new bushing coated in zinc for corrosion resistance, and the heavier duty firing pin return spring.


The newly made parts fit pretty well. So let’s get a few rounds ready to test fire.


The cascabel is threaded into the breech and contains the firing pin in this particular gun. The cascabel is screwed out of the breech and a 10 gauge blank slides in.

The cascabel is threaded back into the breech to enclose the shell. The hammer is pretty simple. Pulling the lanyard hard enough to throw the hammer up into contact with the firing pin sets off the shot. In the test firing video below, I filmed the second of two shots while my friend Sam pulls the lanyard. Not having been used to cannons, he didn’t pull the lanyard hard enough to overcome the weight of the firing hammer. PULL HARDER SAM!!! But the gun fires great now.

{ 2 comments… add one }

  • Kiger July 3, 2014, 12:27 AM

    Jim, You are at it again! The punch is a fine idea!
    Come on out we have a cannon shot here once a year. Will send pictures when get home.

  • Axenboots March 12, 2015, 10:17 PM

    North CA hunter.
    Thank you for your YouTube video on the Winchester model 100. I have to change out the firing pin due to the recall, and you’re the best smith I found.

Leave a Comment