ORIGINAL: Ridge Runner
anything you can stuff down the magwell can be had, in the AR's I've used the 223 8,9,and 12 twist, 25 wssm, and the 458 socom of the three for all around deer/hog hunting the 25 wssm with a 110 gr. accubond is hard to beat, it doesn't hammer them like the 458 socom, but the 458 is a 150 yard max rifle.
in the 223 the 64 gr win powerpoint, the 55 gr trophy bonded and the 60 gr nosler partition are hard to beat. I've taken over 100 deer with the 223 and if and only if you take the "classic double lung on leg foreward shot", any 55 gr bullet leads to a 80 yard sprint to a pileup on our smallish deer here in wv.
ya may wanna look into a 6x45 (223 necked up to 6mm), the 6mm PPC, 25x39mm, if ya wanna get a bigger hammer, the 358/25wssm can be had, (exact ballistics as the 358 win.) the possibilities are almost endless.
RR
where can i find some complete uppers chambered for these catridges that you have mentioned? i've done some searching with little success. i guess i'm not looking in the right places.