For a .223, I like Rock River. For deer, I have a DPMS in 30 AR, that is an absolute tack driver. There aren't any unprimed brass manufacturers available, but the Remington factory ammo is very good. Once fired brass, can be reloaded and I do, w/ Barnes bullets. The 110 gr. TSSX is coming out the barrel at over 3100 fps and is deadly. With 150 gr. bullets, you can get 308 165 gr. velocities in the 30 AR. DPMS also does an upper for the 6.5 Creedmoor but you need a AR 10 lower. This is also a great deer round and in the AR 10 platform is a tack drive.
Bill