I have a brand new never fired battle in barrel originally chambered up for my AIAT. would it be possible to modify / re-machine the tenon for use on my Mausingfield?
The short answer is no. The 2.0 threads are too deep. You could only do it if there is enough barrel left after cutting the AI threads off. They're 1.5" long so unless it's a really big barrel it wouldn't be possible. The Mausingfield needs a .690" max tenon length and 1.20" diameter shank for a shouldered barrel.