Different pistol---new experiment
Kimber Aegis Elite with 20# spring and one piece guide rod---had square bottom firing pin stop---found no discernible difference in performance
My gun---my load---use at your own risk
Sig brass--standard ACP
255 gr Hunter Supply SWC .452
7.2 gr IMR 800X
Winchester Large Pistol Primer
Pure Magic in the ol' 1911
Not chrono'd---no need---good ejection, no primer swipes---no recovered bullets!
The more I use 800X, the more I find it to be the perfect 45, 10 mm, 9 mm powder. I use a Lyman digital auto measure set up so the cornflake design causes me no beef.
Next bullet to experiment with is the Montana SWC GC of similar weight.
Once you get the bug, you can't help but experiment even after finding what you were looking for!