***So far, no one is man enough to fire a .75 caliber rifle.***
No problem in other nations! A 12 guage shotgun shell will fit a .75 inch pipe very well. You can make a nice slam fore shotgun out of them!
But then, the women will again have to start going to the croc infested water holes for water.
Perhaps a quibble, but 3/4 nominal galvanized pipe has an actual inside diameter of .824 inches. 1/2 inch nominal has an actual inside diameter of .622. These are for the most common schedule 40 size of galvanized pipe.
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?