The .45 ACP headspaces on the case mouth. Thus for best accuracy you should trim your cases to a uniform length. This is to achieve uniform headspacing. Use the length recommended by your reloading manual.
And for best accuracy, you should not use mixed brass.
You also should not crimp .45ACP ammo. If you crimp .45ACP ammo, you can get uncertain headspacing in a pistol, which can lead to misfires and or jams.
Finally, Scatch, I'm sorry I overlooked telling you all of this in that last pm.
It is really good idea to trim your .45ACP brass to uniform length.
As for loads, please do not laugh at me. I prefer an old classic powder--Bullseye. In fact, Bullseye was one of the original powders used by the military back in the early 20th century. Bullseye is so thoroughly part of the .45ACP legacy, that I think it ought to be a crime to use other powders.
My favorite load:
230 grain fmj bullet, 5 grains of Bullesye, Overall cartridge length: 1.190"
Muzzle velocity from 5" bbl: 900 fps.
Use this load and live happily ever after.
CAUTION: IF YOU USE A PROGRESSIVE MACHINE, BE VERY CAREFUL TO PAY CLOSE ATTENTION TO WHAT YOU ARE DOING. ESPECIALLY WHEN LOADING .45ACP AMMO WITH BULLSEYE. IT IS POSSIBLE TO DOUBLE CHARGE A .45 ACP CASE WITH CERTAIN POWDERS. AND IF YOU DOUBLE CHARGE A .45ACP WITH BULLSEYE, YOU WILL BLOW THE GUN UP.
IF YOU USE A PROGRESSIVE MACHINE, YOU SHOULD PROBABLY USE A BALL TYPE POWDER SUCH AS HS6. SUCH POWDER IS NICE AND BULKY AND IT FLOWS NICELY THROUGH A POWDER MEASURE.
Mad.