I shoot a 50 caliber flint rifle, 40 inch barrel, 1 in 66 twist, round bottom rifling. Have found over many chronograph sessions that the load I selected pre-chronograph as the most accurate also delivered the most consistent velocity with the least amount of deviation in velocity shot to shot. That load was 75 grains of 2F GOEX. Experimented with Elephant when GOEX was hard to get for a while. The most accurate load with Elephant was 100 grains of 2F. That Elephant load produced almost the same average velocity as the 75 grain load of GOEX, but with even less variation in velocity shot to shot. Extreme Spread and Standard Deviation were substantially better than all of the other loads. Consistent velocity is paramount to accuracy, particularly as you increase range. Ball diameter, patch thickness, loading process consistency, and lube all have an impact, along with the "ideal" powder charge. It also seems from these results that any given barrel may have a "sweet spot" velocity that delivers the best accuracy. Powder brand, granulation, and ultimate charge may be a surprise. The hottest powder may or may not deliver the best consistency. Chasing the best combo is part of the fun.