I have an M96 Swedish Mauser, the finest looking and shooting rifle that I have. I have no problem getting ammo, I buy mine online. I fire PPU 129 grain and 120 grain Match and this rifle is crazy accurate! The wife enjoys firing it as it has very little recoil.
Great rifles and that 6.5x55 will be fine for anything in North America that you want to eat and isn't looking to eat you first. It's all about shot placement and bullet performance.