Pack Rifle Project caliber selection

[Blacktail]

Been contemplating building a light pack rifle. When i say light around 7-7.5 scoped. Was thinking bout the 6.5x284 but have read a couple of articles i am not sure if i should go that route or maybe the 6.5 remington mag. Was thinking this may be the better way to go especially for availability of brass. Any thoughts and suggestions. Thanks