I feel lucky if different weight bullets DO impact close together. I have a 35 Whelen that puts 225 Accubonds about 1/2” higher that the 200 Accubond that’s a bit higher velocity. That puts them pretty close together down range.
What powder(s) are you using?
One thing I've found during my experiments at very different temperatures is that POI can vary considerably with temp-sensitive powders.
An example from 20+ years ago was working up two loads for my .338 Winchester Magnum, one with 200-grain bullets and RL-15, and another with 250s and H4831 Extreme. They shot close to the same place at 70 degrees Fahrenheit, but not at 90 degrees in Africa--or at around zero F. in Montana.
