Hello. Yes you got the general idea. I chopped some old barrels up to see if I could machine them to re sleeve them. Bit of a skills test and not that difficult once I had fathomed out how to do it I cut the barrels off a bit longer than needed and welded a peg into one barrel to hold in lathe then just bored that chamber out on lathe. Then I cut off the barrel I did not need and welded the peg into the other barrel and bored that one out. Dead pleased with myself. Never got around to turning up new tubes to fit , but thought about pistol sized tubes to make a Howda type pistol. Never progress as that would be illegal in uk. Enjoy
Thanks.