Yes, I understand what you are saying but if you are out waiting for crows and a fox presents itself for the taking and there isnt take to swap from forty grain to fifty grain what do you do, also some bullets might have a different point of impact
Unless I am just going out for rabbits(.22lr used) then I will carry my 6.5 if doing personal foxing/stalking and if I am doing paid deer control then it's the 270. Both all species legal. I shoot a lot of deer compared to foxes this is why I dont have a "foxing" chambered rifle. This morning I shot 1 fox in the head, a sika and a roe through the shoulders, all with the 270 no problems, if or buts. All dead on the spot, deer in the larder ready for game dealer. Dead is dead.