Does anyone have a method to get two loads to shoot to the same point of impact. I'd like to be able to use some of my rifles with a light fast opening bullet for goats/varmints etc and a heavy bullet for pigs and deer?

I've got a 300 Weatherby which shoots 150, 165 and 180gn maximum loads to the same POI and it has some upward pressure on the barrel at the forend tip - could this be the answer?

I know the simple (but expensive) answer is two scopes in QD mounts and the simple but (risky answer) is to count the clicks and adjust the scope. I'd like to be able to just pull a different cartridge out of my pocket and swap, say a 130gn 30-06 Ackley load for a 180gn load.

All suggestions gratefully accepted.

mike