[BwanaNdege]

Quite a nice selection of paintings you have on your homepage! I can paint a wall, but that’s about it.

Somewhere I have a copy of “Edge of the Anvil”, but have never done as much with blacksmithing as I’d like.

So, 3/4” G.I. or black iron pipe would make a 12GA barrel? What about 1” mechanical tubing, 0.120” wall, wrapped with piano wire & brazed/soldered? That’s about 0.760” bore - 12Ga is 0.729”, so maybe too loose? Shells split?

[Ruy Dias de Bivar]

I guess some use black water pipe. I personally would prefer to use heavy wall seamless pipe. If I fired one of those I want to make sure I still have hands and fingers left.

[marktwain]

It should work just fine. If the shells are a bit loose, just wrap them with masking tape until they fit to your satisfaction. I believe you can go a full gauge smaller with this method and it will still work just fine.