Contrary to common belief the 6,5x55 was not developed by Mauser, but was constructed by a joint Norwegian and Swedish military commission and introduced as the standard military cartridge in both countries in 1894. It has proven itself an extremely effective all-round cartridge ever since. More than a hundred years after its introduction it is still the standard round for competition shooting and one of the most popular hunting cartridges in all the three Scandinavian countries. Having downed a dozen moose, more than 50 caribou and three times as many roe deer with the 6,5x55 it remains my all time favorite choice for mixed European hunting.
The reasons are obvious. The moderate velocity and the long bullet combine a mild recoil and very deep penetration - decisive factors for good shooting and a quick kill - and thereby a successful hunt.
With properly constructed bullets it is considered adequate for all game from black cocks to moose. This is well documented by the fact that every season tens of thousands of moose are killed with the 6,5x55 in Norway and Sweden.