I have a Ruger 45 convertible 45 Colt - 45 ACP I got new in the late 1970's. For years I shot cast bullets in it -as cast- which were more or less 0.452" with 10 yard accuracy that was just Okay and nothing more. My Super Blackhawk was much more accurate and was my plinker of choice. To see what was going on, I had run soft 50 cal round balls through the cylinders and found 0.456 and 0.457" diameters. The ACP cylinder is large too! Goofy.
LBT made me a 4 cavity 45 Colt mold of the correct nose profile to match the factory stuff and at his suggestion a much larger diameter. The mold casts great bullets at 0.457+. The handgun as been living in the back of the safe for 30 years because it is just not a great gun. I started working with it off and on the last few years and found the RCBS seating die is not large enough to seat the 0.457" bullets with out shaving the bullets on the way in despite the fact I have a custom expander that opens the case to 0.456" and flairs the mouth to 0.460". Accuracy with the shaved bullets is not all that great either.
In any case, I am going to be shooting 0.457" bullets through a 0.452" barrel.
I am thinking about trying to make a die body slightly larger just to seat the bullets. Any advice on going this route?