Saturday, February 5, 2011

Making A Firing Pin

A friend of mine purchased a Ruby Pistol at a gun show. We went shooting and the gun barely struck the primers of the PRVI 32acp he was using. When we got back to my place, my friend used a punch to push on the firing pin (where the hammer would contact it) and saw that the firing pin barely protruded from the breech face. It was time to make a new firing pin.

This Ruby Pistol is marked "Looking Glass" and was made in Spain probably during the 1920s or a little before. There were a bunch of manufacturers of Ruby Pistols. Quality of a Ruby can be vastly different between manufacturers. The parts from one Ruby to another are usually not interchangeable either, especially if the user is trying to put parts made in one factory into a gun made in another factory. Each factory was a separate business and some of them did things differently, working to unique tolerances and measurements. A new firing pin just couldn't be found, so we spent a Friday night making one.

The old firing pin appeared to be brass or bronze. It was not coated or plated, that part was gold in color all the way through. It looked like someone had made that firing pin and we were about to do the same, except ours was going to work. While talking to the owner of the gun, we kicked around the idea of sacrificing a pin punch to make a firing pin. The owner decided to try pegboard hooks. The diameter looked about right and the material was probably sturdy enough. Why not, right? If anything, I thought the pegboard hook would be easier to work with than a punch.

We used a digital caliper to measure the thickness of the firing pin. The pegboard hook was slightly smaller in diameter, but whatever. Without a lathe on hand to get the slim portion of the firing pin down to the right size, we put the stub of metal into a drill and ran it across a bench grinder, then a file. The grinder worked a little too well. I wrecked a couple of potential firing pins because the bench grinder in conjunction with my spinning drill just took off too much material too quickly. The way to make this firing pin was to use the bench grinder/drill combination to start, then do the final touches against a file, which I had secured in my vice.

It is always easier to take off more material. Its not as easy to put it back on. We ground off a little, then checked the size, then went back to the file to grind off more. After a good two hours of us messing around, we had a finished product. The gun owner put the new firing pin in his gun, then I got out my bullet puller to pull the projectiles out of some 32s. I got a round of Winchester, a couple rounds made by S&B, and a Fiocci. We wanted to try different brands just to see how it would ignite different primers. I didn't want to shoot a full round of 32acp in my basement, so we used my bullet puller to pull the projectile and powder from each shell casing. Then, the gun owner tested the gun by chambering a shell casing and pulling the trigger. Just the sound of the primer wasn't too loud, but was enough for us to know that the new firing pin was capable of lighting off various primers.

It was fun and our first time making a gun part from scratch. My friend from Brookyln had joined us that evening. He had zero gunsmithing experience, but I think he enjoyed himself doing something a little handy.