I have two 625's - a 5" Model of 1989 625-6 and a 4" JM Special 625-8. Both are in .45 ACP and are two of the best shooting revolvers I have ever owned (and that has been a bunch). They have become, in the last three years, my two most used revolvers.
If yours are like mine, you have a DANDY!
I cast my own bullets and shoot a Mihec clone of the H&G #68 200gr SWC at target velocities, mostly. However, I also have a NOE mould that throws a 250 gr Keith (454424 Lyman clone) which is suitable for deer hunting (you can safely and easily get 900+fps which equals or exceeds the original .45 Colt load with a MUCH better shaped and more effective bullet). The original .45 Colt was spec'd to shoot through a horse at 100 yards (U.S. Army standards), so that is pretty good company.
The cylinder throats on both of my revolvers are right at .452". I size my bullets at .452" for a perfect fit.
Good shooting!
Dale53