Well, I would re-think the dualcompetition/hunting uses. Ibought a Rem. 700 and sent the action off and had an M40A1 built and, like you, I wanted to use it for both competitions and hunting. I competed with it for a few years in F-class competitions and hunted with it once....and ONLY once. The thing was so damn heavy that I told myself that I'd never do that again. Will it shoot? Of course it will. But getting it from point A to B is a nightmare. I couldn't imagine hunting with it in the mountains let alone flat ground.

Point being, whatever your choice of caliber is really doesn't matter, as both will do the job. The platform that you choose will definitely be the most important decision though. Either goheavy barrel for target shooting or light weight for hunting. Heavy weight for hunting will only make you tired and light weight for target shooting will burn your barrel up sooner than expected.