So I got the new mold for the 480, they drop at .478 and 392 grains, my .476 sizing die sizes them down to .477ish. So I have loaded and fired about 100 so far. Well I was thinking that I was going to have to send my pistol to a gunsmith to have the cylinder throats opened up and uniformed due to the difficulty of chambering the rounds. Well as it turns out, my problem was too much crimp and it was causing a slight bulge (these Ruger chambers are tight!)which was causing the difficulty. So I have reduced the crimp, they chamber very nice now, and given the amount of case tension on the bullet, I don't see the reduced crimp being an issue, but I dd go ahead and order a Redding profile crimp die as they work really well on my 44 and 454. I don't shoot this pistol as well as my 44 or my 454 from a rest, but it sure shoots great when I shoot offhand, I get 3 to 3 1/2 inch groups from a rest, offhand I have fired groups that are in the 1 1/2 to 2 1/2 inch neighborhood. I am really growing to like this pistol.

I had that happen once. Gotta be careful when applying a heavy crimp or you may deform the case.

Too much crimp on any bullet can actually SWAGE it down
in size.. lts easy to prove by first measuring an unseated
bullet. Now take that same bullet and load/seat/crimp it
into an empty case..Now its time to break out the old
kinetic bullet puller and break that round down...
Measure your recently seated/pulled bullet...You will be amazed
how your .430 bullet can turn into a .428 or .429 one..
Tossing accuracy out the window.. l crimp as little as possible
and choose the lightest brass...

I think the issue of swaging a bullet down is more of a factor on dies that taper crimp as opposed to ones that add a roll crimp.

On my roll crimp dies (Lee and RCBS) I will begin to crush the case before the bullet is swaged down. This manifests itself as a ridge running around the case, just below the bullet. Same as the issue seen by AKBman.

On cases like a 45acp or other taper crimped cartridge, too much crimp will definitely result in a swaged down bullet. The same can be said for even correct use of a Lee Factory Crimp die.