Nothing wrong with using necked down .284 brass for hunting, but this poster mentioned long range benchrest as well. For that I'd use Lapua 6.5-284 brass that's been match prepped, weighed, etc. You've got to be seeing SDs in the low single digits to be doing much at 1000 yd and not have too much vertical dispersion. As for actions, we've had good luck with blueprinted Remingtons, the large Panda, and using Speedy Gonzales's sleeve to make a Rem look like a Panda so you can use proper stocks. They all work, but a gun to do both this game and hunt as well wouldn't work too well for either. Best to build two rifles.