...I wondered how difficult it would be. Turned out not bad at all.
My Lee 3-piece dies arrived yesterday and I got started. I decided to be even-more careful than I usually am in setting the seating die. I started with the loose barrel and slide. There was minimal play of the barrel in the slide, and that remained with 3 different factory loads. I adjusted the sizing die to reduce that slightly with sized-cases-only in the chamber. The mouth-expander/charging die ended set to bell the mouth just visibly. I set the taper-crimp die to just visibly crimp the mouth, and set OAL at c. 1.135".
I started with Berry's 125g. plated HPs, my goal being to create a high-velocity-but-inexpensive practice round that made spectacular kills on water jugs. I already had WSF and Longshot powders and bought some 800-X. Loaded 5 rounds each of 10 loads and tested them for function, etc., late yesterday (until my chrono wouldn't work in the gloom). Evaluated 10-each today and got higher velocities than I expected ven tho I'm using a 4-1/2" Lone Wolf barrel in my 32. Velocities at 10 feet got to the mid or high 1400s with Longshot and 800-X, respectively, but group sizes with WSF were significantly larger than those from the other 2 powders, so I won't be using WSF with the XTP 124s on the way. Can't yet find Accurate9 locally or I would have tried that too.
I blew up a few 1-gallon waterjugs with the Berry 125HPs and both bullets stayed together better than I expected. Won't be using them for PD, tho.
The factory-loaded Speer Gold Dot 125 performed approximately perfectly, as I expected.
I'll e-mail an image of my data if you request to jeffreybehr(at)cox(dot)net, but the usual warnings apply.
This longer-barrel-snouted 32 will be a keeper, as will my pair of 37s (.45GAP) for USPSA competition in Production class.
I intend to research muzzle flash with various powders, since my otherwise-fave in that area, Universal, isn't very suitable for the loads I want.