Speaking as a hunter and target shooter, I've seen significant difference between powders. I used the powders I had, bought one or two more, and borrowed others. I don't mind playing around with variables. I also received advice from others with the same cartridge. Ended up relying on the advice as NoMercy suggests. Was loading for a .243 before going to Wyoming.
Weird thing is I shot a much better group with the bullets loaded by my friend than those I loaded using the same recipe. The only differences were our reloading equipment plus he used match grade primers. I have yet to delve farther into this in an effort to determine if it was a fluke or if the reloading equipment was the factor besides the primer.
NoMercy, do you believe match grade primers make a significant difference?