If memory serves me correctly, it doesn't always nowadays, I remember reading an article (or series of articles) I think by Sherman Bell in the DGJ regarding how using different weight bullets, shapes and powders & charge weights can be used to regulate a double rifle when the load data used to originally regulate the gun is not available. Things like if heavier bullets tend to bring the impact point closer or further apart and if pushing bullets faster will force them further apart or closer together.
Anyway if anyone knows which issue(s) this article was in I could use the help finding it...
Thanks in advance.
WBLDon