[amamnn]

Unless you are shooting for long range accuracy, it's doubtful that you would see much, if any, difference between the major brands of primers. If you buy your primers 100 at a whack, you will be using primers from different lots over time.
In my plinking loads and when I used to hunt, pretty much any primer would be ok. I got into loading for competition and varmint hunting at long range and got into the accuracy quest up to my ears. I had the opportunity to test lots of primers, and found that the only real difference in the performance of a load with different primers used was in consistency from round to round over a large number of rounds shot. Within 100 to 150 yards, the difference was so small as to be negligible in standard primers. Outside that range the difference was still quite small, but in competition one is concerned about a 1/16 MOA or less in EVERY shot as the difference between first and second place and etc....I've only had one primer ever fail to fire. It was a benchrest primer that turned out to have no chemical in it. QC was asleep when that one was made. I won't mention the brand because I figure that could happen with any primer.
I have not experimented extensively with magnum primers, but they follow the same trends I am sure.
I buy Federal Gold Medal primers for my competition loads and federal standard primers for everything else. If I were to run out before I could get my next 1000 primer order, I would not hesitate to go buy some CCI primers.