Setting up my first reloading experience. I have been shooting Nosler 69 gr. HPBT factory rounds from my .223 Remington 700P with a 26" heavy barrel and a 1:9 twist. I have new Nosler brass, Nosler bullets, and CCI BR-4 primers. I have been shooting 1" minus groups at 100 yrds. and think I can make that tighter if I reload. Which powder would be the best given those criteria?