DIY Breech Plug for a 12 Gauge smokeless single shot barrel

[theoldredneck]

I have bought a few cheap import flintlock wall hangers that have welded breech plugs. Used a thin cutting wheel to remove plug and see just how well they were welded. Welds were very shallow, probably a torch weld. Not something I would trust to shoot. I learned to weld in my cousins welding machine shop as a kid. Welded gas and steam pipe as part of my job for years. Have no doubt I could weld a breech plug in that would work fine. That said I would not weld a breech plug for several reasons. First it does not take that long to tap a barrel and fit a breech plug right. If you need to you can remove it if you have to knock a ball out. Never talked to a old muzzle loader shooter that hasn't dry balled or helped someone that has. Some of us old farts are better at it than others. I'm thankful at times for screw in breech plugs I can get out. Told an old friend I may have to use Velcro to hold next build together and one of those modern inline type breech plugs on next flinter. LOL

 

[Zonie]

I'll join the "don't weld it" camp on this one.

While welding is commonly done on pipes, a gun barrel is not a pipe. Pipes can be subjected to high pressures but the pressures are gradually applied, even with the quick opening valves used in hydraulic systems. That is very different from the rapid explosive force created when a gun is fired.
The explosive force can be thought of as a "shock" condition. The amount of stress produced by a shock condition is roughly twice as high as the stress produced by a gradual force.

Also, with any welding there is an area around the weld that is referred to as a "heat effected zone". These heat effected zones are always weaker than the material outside a heat effected zone (unless heat treatment is done following welding to restore the material's properties).

Simply put, properly threaded breech plugs are always preferred to weld joints when it comes to gun barrels.

 

[okawbow]

My 12 gauge flintlock turkey gun is made with a 36” (originally) modern shotgun barrel. The chamber was cut out close to the forcing cone and the barrel threaded for a 7/8”-14 plug.
I tested the barrel to a 3x maximum overload with no problems. I have shot more tha 12 turkeys with that gun.