20" Rossi 45 Colt El Jefe
Ruger level load, based (conservatively) on 225 gr and 240 gr jacketed bullets With H110 on Hodgdon's site:

45 Colt
230 gr .4515 Moly RN (45 ACP bullet from Precision Bullets)
23.5 gr H110
#350 CCI magnum large pistol primer
1.600" OAL
½ turn Lee factory crimp die
Starline brass

I ring a 3/4-size silhouette at 200 yards consistently with this load. Muzzle velocity averages 1715. This thing is COOKIN'!

No leading. No flattened primers.

I haven't tried it in my Old Model Vaquero yet. Not sure that I want to.

I use a Frankford Arsenal Intellidropper for all rifle loads. I get very low extreme spreads in velocity. My last batch of the above load had a spread of only 16 fps for 5 shots.