Winchester has done it with these T7 209 primers, at least in my Sidekick. I went to the range today with .50 Sidekick-3x9 Redfield widefield. I had been geting crud ring with 90 gr. T7 and standard 209 Wins. Shooting 300 gr. SST over 90 gr. T7 and noched same hole-three shot group at 50 yrds. The best part is no I say no crude ring at all! By the way throw the Hornady sabots away and use Harvester Crush Rib sabots,they load so easy didn't have to use bullet starter! Any ways I hope someone can use this imfo.