If the cartridge is capable of winning 1000 yd matches, then It's capable of killing at 300-400yds on critters like mule deer and elk. The very thing that makes the 6.5x55 and 260 capable of winning long ranges matches [sleek bullets that shed velocity very slowly and drift grudginly] help them carry the needed energy to expand bullets, break bones, and destroy tissue.
I once read of Clay Harvey killing a NC black bear at around 200 yds with a 6.5x55 and 160 grain bullets. The bear weighed almost 500 pounds. One of those long 160 grain Hornadys when thru the bear from stem to stern. If a 6.5x55 will shoot thru 6' of bear, I think a 260 can handle 15-20" of elk chest.
