Some years back I measured the barrel dia.s at various points along both a BC 45-70 and a TM 38-55, they were the same. The U.M. 2pc I have from a gun show table fits my TM, my 12ga bird, 12ga. Buck, and my 20ga. bird barrels.
Because I havent decided just which one really gets it I have not epoxied it in place on anything, but certainly would. I have found that even if tightened down well, it can have a tendency to 'twist' a bit in use, which will mar eventually and does not give me great confidence.
Degrease the parts a couple of times and JB, let cure for several days and it should be good to go (make double sure it is straight & square on the 'stud line').