I've seen moose killed with all 3 cartridges, with the .300 WinMag giving the poorest performance and the .308 the best. Of the 40 or so moose I've seen taken, the most consistent performers have been the 30-06 and the .35 Whelen. The largest moose ever taken from Parry Sound District in Ontario was shot in our camp with a .270.

Of the 10 moose I've shot myself, 8 were with a 30-06 and 2 with a .303 British. Since I use expanding bullets, the performance of these cartridges has always been exceptional.