When I was at my gunsmith's shop he showed me a sxs shotgun that he was working on for himself. It had the right barrel blown out. He placed a mandrel down the bore and hammered back the pieces, proberly a bit of welding as well, then sleved a 45-70 barrel down there. It was fitted with a front sight and a large "ghost ring" type rear sight. The 45-70 barrel was sighted in for 50 yards. Now I reckon it would be perfect for the type of pig shooting I do in the creeks and swamps. I had a shot and found it didn't kick as much as my mate guide gun.

Bakes

I would have thought the pressures of a 45/70 would be to high for a shotgun action.
What sort of loads was he using?

I asked the same question. He's using factory rounds, winchester I beleve.

Bakes

I don't think the pressures would be too high for use with 405-grain factory stuff, which can be fired in the trapdoor Springfield. I'm sure the barrel walls are much thicker now, and the total case backthrust would be less. Straight cases grip chamber walls when fired, and the casehead area is much less for a .45/70 round than for a 12 or even 20-ga. shotgun shell.