you've gotten alot of good advice here... I use 250 grain lead in both my lever & Vaqueros, I have a boat load of 200's, but they shoot low, I use 5.5 grains of Trailboss, & a 250 bullet, I still needed a little front sight filing, but now mine shoot exactly to point of aim at 40-50ft...
BTW... I use mostly CCI primers in my matching pair of Vaquero Montados, & never had a light strike ( though I've not trimmed my springs, or some of the things the gamers play )
as far as magnum primers, I don't think they are needed in the 45 Colt, until you get to loads aproching the 454 Casull in power / powder volume... I do use magnum primers in my very hot hunting loads I shoot in my Contender
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