Pappy,
As noted in the chapter on primers in THE BIG BOOK OF GUN GACK, I do know the only difference between CCI "BR" and Federal "M" primers and the standard stuff is more consistency, partly (but not totally) due to the people trained to spread the compound more consistently. This probably won't make any noticeable difference in the accuracy of most rifles, and may not even in super-accurate rifles. But the BR's and M's are there for people who want everything in their handloads to be as consistent as possible. (I don't know how Remington makes 7-1/2 small rifle "Bench Rest" primers.)
I've gone through the same choices everybody else has during this high-demand, low-supply period, and a couple of years ago decided to switch to primers I could find and buy. I'd been using CCI 200's and various CCI small-rifle primers for many years with fine results, but had generally used Federal 215's for magnum primers. Tried CCI 250's in the same loads I used 215's (or 215M's) in and accuracy was a good or sometimes better.
Still have a smaller supply of other brands of LR primers, just because I need to include them in testing for articles, but stocked up heavily on 200's and 250's.
After considerable experimenting with small-rifle primers, settled on Tula KVG223's as my "mild" rifle primer, and CCI 450's as my magnum. (The 250 also works fine in AR-15's, due to the thick cup.)
Most of this was done with on-line orders during sales, when buying in bulk made them a very good deal despite the hazmat fee. Once in a while I find CCI's for a decent price in stores, but on-line is my main supply source these days.
