Favorite primer? Thats a loaded question.
(Pun Intended)
I was using Federal primers for everything, until I started loading for my 17Rem. It was brought to my attention by a very intelligent person that the Rem 7 1/2 was made for the finnicky pressure spikes of the little 17 and had a heavier cup. Believe it or not, I got better groups instantly, with no pressure signs (the Feds were boarderline on pressure) with the Rems.
Soooo, I guess, I dont have a favorite anymore. Probably going to re-evaluate on some other calibers and try some different things in the near future.
Andy