Haing never loaded for these calibers, a friend of mine wants too and asked me to help...well, I am a little puzzled having never researched these calibers and now realize they have a .451 and .452 dia bullets. I see the book calls for a .451 in the acp, so, what I am wondering is can you use a 451 in a long colt or a 452 in an acp? He has plated bullets. Anyways any further education from those who know would be great.