They're marketed as such but looking at the specs the BR4's pretty much match the 450's. Only CCI really knows for sure if they're identical. The BR4's aren't the same as the 400's, that's for sure since the cup thickness is heavier. Maybe the 450's are hotter since they're labeled "magnum" but most guys that I've read who've tried the 450's vs. the BR4's in the 6BR and 6.5x47L say they can't tell the difference. I've tried both of them and I can't tell any difference so now I just buy the 450's and save $20 a brick. Federal will tell you that their match primers are the same as their standard primers with the exception that they go through an extra inspection step. I'm inclined to believe that's the same with the CCI450/BR4 but maybe I'm wrong.
I wish my 223 couldn't tell the difference ........
