The reason old people become stubborn IMO is because they see the world changing drastically and not for the better! It creates some pause concerning change and for good reason.

If I was loading for this old man I'd simply find a load to duplicate what he has been shooting and don't touch the damn scope unless you want to ruin it. Easy enough to find a load that will shoot to the same point of impact.

Trystan

Good bullets properly placed always work, but not everyone knows what good bullets are, or can reliably place them in the field