I handload, so ammo supply and variety isn't the real issue for me. I imagine that like so many other cartridges out there, brass will be around and available long after factory ammo offerings dry up. I'm attracted to the 7mm RUM over the 300 RUM mostly because of the higher BC bullets in common hunting weights, and the similarly flat trajectory with 20% less recoil. The .300 RUM hits a little harder downrange, but the difference isn't so great that it'll matter until the range gets beyond 500 yards. With a muzzle brake the 7mm RUM with a 9.5lb rifle should kick like a .270 Win.

Mike