I'm not at all JB...
But I've a couple of years shooting competition, at some fair distances, and with some fair guns and fair results.
What I can say is while I try to research and find which primer might be most common with which powder, I keep every brand on hand that I can find...
I have found, that primer choice in a given load can do anything from cut group size in half to double or triple group size to almost no change at all.
Obviously you might skirt this by continually searching a load though... I mean if you are having issues with X grains and Y primer, Y primer can usually work if you keep playing with all the other variables.
In the end having primers is obviously better than having none. Its why I try to keep on hand a couple of cases of the top choices.
Some things are no brainer combos.. like Varget in a 223, you need look no furhter than CCI BR4. But you can get others to work almost as good.
Granted I"m usually pretty picky about accuracy. Even with factory guns.
