Trigger control and front sight in focus. If you can't do those, ammo doesn't matter.

I shoot a lot of bullseye matches and frankly, I shoot mixed brass and have never cleaned primer pockets or trimmed brass. I load on an SDB. The only thing I do for accuracy of my 50 yard loads is to make sure those bullets don't have any dings on the edge of the base and I don't use bevel based bullets. Don't weigh bullets, either. At ranges 25 yards and less, you can load rocks and still get 3" groups if you can remember trigger control and your front sight.