q1. top of the range deer stalking rifle with well tuned loads and a competent shooter? 1/2" to 1" in decent conditions.
q2. there is not really a chambering that shoots inherently better than any other. recoil, bullet choice, ballistic co-efficient, bullet speed start to come into play at 300m. a fast 6.5 chambering would be my choice for 300m.....
apologies for going off topic in my previous post, but i wasn't the first to do so.........
Will a stalking rifle really hold that kind of accuracy at 300m? That's less than 0.3MOA to 0.15MOA. I might get a lucky group around that, but I certainly could not consistently do it.

