I got the 5.5" barrel. Plug gauges show my cylinder to be .429 in all throats. I haven't been able to shoot a whole lot since I got it but about 50 rounds loaded with a couple of cast bullets from RCBS GC molds were sized and lubed in a .431 die. Lube was NRA Alox that I mixed myself. These bullets shot well, at least to my level of competence. No leading.