Rmiller, you are playing with fire and are going to get burned. Get rid of those bullets and DON'T shoot any more Unless you load them for what they were designed for, the .45 Colt. That bullet is too light and also too lightly constructed for the pressures of the .454 which can go as high as 65,000 PSI. The bullet turns to putty and you are shooting the cores out of them. This not only pushes pressures way into the danger zone, but you will leave jackets in the forcing cone or bore and if you shoot another behind it, you will blow up your gun.
Buy the bullets that are labeled for use in the .454 ONLY.
This was an occurance back when the .357 Super Mag came out and now we have a whole list of revolvers shooting in the rifle pressure range. Each one of these needs strong bullets and you MUST be sure of what you are buying.
I would go to a good hard cast boolit like the LBT's myself. Be careful so we can keep you here for a long time.
WHAT YOU ARE DOING IS DANGEROUS!

Yeah, what bfrshooter said. You can use the Freedom Arms bullets, Speer. Hornady magnum bullets and drive them to the velocities capable from a Casull. Most all others just can not stand the pressures. Hard cast is another good option and the LBT is a most effective game getter bullet.