I have learned the hard way with 454 Casull, if you want a 45Long, get a 45long. After several thousand rounds, I had trouble getting 454 rounds in and pressure signs. I had to get my gunsmith to slightly ream out the cylinder. Since then I load down 454 casulls.

Most people can go thru life and never have issues like this, but if you do sparse cylinder cleaning and shoot several thousand rounds, you will end up with issues one day.