I would tell him to give up the gun… buy a pair of crocks and set himself up infront of the tv. He has no business being out in the hunting world

I would be polite and just never have time to do anything beyond advice. If he won't take your advice don't waste your time. If he does then a little range time.

to flatter not harder hitting

between 100 and 200 yards 270 is 1/2 inch flatter
between 200 and 300 yards 270 is 1 1/2 inches flatter

but the heavier bullet still has the ability to hit harder and since Wolfie had repeatedly said it's hard to get more than 100 yards unless you have a pasture to shoot across the dude probably insn't in need of that flatter trajectory since all shots will be inside a 100 in most cases

the dude needs to put some on paper to realize how far off he is or that he flinches at recoil

1986, B-2-3