RE: Different Grain-Same Gun
I've found very little if any POI on all my loads for the same rifle. Most of 'em require no tweaking to the scope.
I know in my 243 I can shoot 60gr, 75gr, 95gr bullets all with the same zero and kill whatever I want out to 300 yards easily. If I know I'll be shooting farther than that, I will spend some time dialing in the bullets to the scope.