Howdy,
Mikey turned me on to the Lyman #452423 bullet, a 240 grain SWC designed by Saint Elmer. Being a curious sort, I managed to find double and single cavity mould blocks and poured a bunch of them. I loaded some with my nutcracker tool over 5.8 grains of Unique and my Chi-com 1911 has never shot better!
The SWC has more bearing surface than the RN, and I sized them .452" also. Recoil is stiff, but there are no signs of over-pressure. The pistol groups better with this bullet than with the FMJ's that I have been shooting.
I'm not sure I'd want to try loading a heavier bullet, though. It would seem that the tapered case walls would prevent a relatively long 250 weight bullet from seating deep enough for the pistol to function correctly.
After trying the Keith bullet, I may even buy a set of 7/8-14 dies for the Rockchucker. Thanks, Mikey!
Bitterroot