Ever broken a firing pin? If you’re like us, you have, and then you either ordered a firing pin replacement, or had a gunsmith make one, if there was no factory or used firing pin to be had. Or maybe you just hung the weapon back in its place, your equivalent of the “too hard” file on our desk. This excellent video from the American Gunsmithing Institute (yeah, those guys that want to sell you approximately a million videos for approximately a million dollars) has gunsmith Ken Brooks in show-and-tell mode as he restores a firing pin — in this case, for a Winchester Model 1894 .30-30, but the principles apply whether your broken firing pin is in a Luger or a Lewis gun1.
It was rather eye-opening to us that he applies no heat-treating to the finished part. The spring-steel stock he uses is already heat-treated, of course.
The most valuable information in his entire presentation (which we watched raptly from end to end) was his description of the specs for firing pin fit and protrusion, and his reduction of these to simple rules which work not only for low-pressure blackpowder-era cartridges like the .30-30, but also for high-pressure modern rounds.
Next was probably his warning of the necessity of washing off soldering flux. Fine and good to solder the new pin in place, but his description of what happens if you let your customer go tripping out the door of your shop
You can extrapolate from here to some common firing-pin related problems you may have encountered. Light strikes or no strikes? check protrusion. You could have a short tip, or a firing pin held back by corrosion.
On some frequently-broken firing pins, Ken’s techniques won’t apply, for example on the simple turned firing pins in Tokarev rifle and pistol designs. (Both firing pins have a design weakness, in that they have a large cutout for a retaining pin. Coupled with wartime manufacture that short-cut deburring and polishing, they are very prone to breakage at the corners of that recess. A little bit of bench work is in order if your firing pin has sharp edges or other stress risers in this area). But those pins are relatively easy to make, if you have a lathe.
Yet it turns out that this kind of pin is, if not easy, quite straightforward to repair. Repairing an original part detracts less from a gun’s originality than replacing a part, which may be a factor
Hat tip, the NRA.
- Hmmm, we might have overstated that. We’re not sure there’s enough material in a Luger firing pin (which is mostly hollow) to replace the nose and meet Ken’s at-least-half-inside requirement. And a Lewis gun’s firing pin is part of the operating rod, and if it does break, may break where a soldered-spring-stock repair is not practical. Fortunately, it’s overengineered and seldom breaks.
Update, surprisingly related:
The NRA reports that the State Department is trying to ban the internet publication of technical information like this and other material hosted at this blog. This is not surprising from those Game of Thrones wannabees. We intend to carefully read the proposal (.pdf; the State Department wall of verbiage begins in the lower right corner), run it by our ITAR consultant in the day job, and react accordingly.
We guess: the gun-banners in striped pants at Foggy Bottom are not going to like our response.