After working with a dozen or so 243s, which is far and away my favorite small bore, which explains why I have 5 in my rack right now, I have found almost universally with all bullets from 80 grns and up that max loads of IMR 4350 with a CCI 200 produces the best velocity and accuracy. 80 grn bullets also have the distinction of getting the highest velocity per gn weight in the 243, but are marginal big game bullets and not my choice were I to hunt BG with it. I have had superb accuracy with most of my 243s and almost any bullet you want to use up to 100 grns. I have shot out 2-243s utterly and completely with each having more than 10,000 rounds through them, did I mention I loved the cartridge. Now that I have 5, I don't anticipate another shot out barrel and I don't get out near as much as I used to. As H4831 stated before this post, maximum loads almost always are the most accurate and our experience is virtually identical even though he likes the ball powders and I the stick, the burn rates are identical. If you really want to throttle the 243 up to max, use W-W brass or Lapua, don't use Fed, Horn or anything else, W-W and Lapua will allow you to add 100 fps to the max of this cartridge, but other brass will NOT. Just in case you wanted to know that...............