It would seem that the mechanism that makes your gun go bang should be simple to understand and evaluate. But the various types of firing pins cause a lot of confusion among gun buyers. Here’s what you need to know before you buy.
Virtually everyone knows that a firing pin hits a primer to set a cartridge off, and there are a lot of methods in getting that operation done. There are too many designs to list them all here, but it’s worth looking at the types you’ll likely run into when you’re considering a gun purchase.
There are usually quite a few parts to a firing pin, but a few parts are more visible and important than others. The nose is part of the firing pin that hits the primer. The pin has a shoulder, which is the larger diameter from the nose of the pin to the main bulk of the pin. The spring recess is the hollow portion of the striker body that holds the firing-pin spring.
Revolver Firing Pins
Most wheelguns use passive or active firing pins. If the hammer is exposed, the firing pin is passive. It remains in the frame and is struck by the hammer or a hammer-transfer mechanism.
If a hammer needs another fixed firing pin, take extra care to see why the thing broke in the first place because it shouldn’t happen under normal circumstances. If the hammer has a hole in the front or a cross-pinning hole in its side, it has an active design.
Active firing pins are usually integral (built into or fixed to the front of the hammer) or swiveling (with a pivot pin through it). Curiously, some S&W models have sprung, pivoting firing pins, while some are unsprung.
Either way, the nose of the pin has to be cammed so it doesn’t hit on the firing pin clearance hole. I prefer the springing style, since it doesn’t involve an impact or scuffing as does the camming method. The latter tends to rupture and tear primers, I’ve found.
Other Common Pin Types
Strikers, commonly found on Mauser bolts, usually have a spring inside the body. The 700 Remington has what looks like a striker, but it is really a quasi-striker system because the firing pin is released by a camming action and not the sear. The transfer-bar system includes a bar or other mechanism to transfer the hammer’s momentum to the firing pin only when the trigger was pulled.
In revolvers, this is usually a bar that lifts up when the trigger is pulled. Some manufacturers place blocking devices directly in contact with the firing pins, notably in the Colt Series 80.
This firing-pin locking-pin style means that several levers must be moved by the trigger before they raise a spring-loaded blocking pin out of the locking notch in the firing pin.
Before You Buy
At some point, someone will show you a gun that needs a firing-pin replacement, but the pin will be missing. Check exploded views of the action to see the complexity of the pin itself.
Even a basic drawing can suggest the pin’s relative size, the number of pieces it has, if it has a retaining pin or screw, and if it works with a return/rebound spring. All those will influence the design and dimensions of the pin and give you a preview of how difficult it might be to get the gun back in service.
If a gun you’re examining needs a firing pin that’s the striker type, make the deal only if the pin is available from your parts sources. Only a very experienced gunsmith, one who is also a good machinist, can make a good striker.
Scott Freigh’s “Before You Buy” column appears periodically in Gun Digest the Magazine.