I've got a 645 slide assembly that I was hoping to run on my 4516-1. Unfortunately the barrel to frame lug on the 645 barrel is too wide. I measured it at .523" the 4516-1 barrel was something like .486". When did smith change this dimension?
The 645 barrel as well as my 1076 and 4516-1 all have the old style barrel hood (.342"ish) and the 45's fit into each other's bushings fine. Are there any third gens that have the wider barrel to frame lug?