I know your son wants to use the heaviest bullet for some reason. I get it. When I was 16 I thought it was a great idea to use 220 grain bullets out of a 30-06 for deer. Until I figured out I could blow a golf ball size hole out of the deer shooting it diagonally through the center with a 150 that was easier to shoot well!
But for the 7mm-08 go to the Nosler load data page and flip through the different bullet weights, and see what happens to the energy as you go from lightweight bullets to heavy for caliber bullets. The Sweet spot on energy AND mid to long range hunting distance is going to be the 140 150 and perhaps the 160. When you go to the 160, you're actually giving up performance below 400 and even 500 yd, favoring extreme distances that you'll probably never shoot game at.
Just like with a 308. The ideal bullet weight for energy and trajectory in lead based bullets is a 150 and a 165. BUT if you want to shoot a thousand yards, you may have to shoot a real slippery 168 or even a 175. And both of those have a cost you have to pay between 0 and 500 yards.
I'm not meaning to be a jerk at all. And a 160 plus bullet will definitely work for you. Well for what you're doing it's probably not the best.
Now if you want to step up to a 7 mm 280 AI
It'll take that bullet right on to 175 and sail with it. But 41 grains of powder out of a 20 inch barrel Lane helping you any.
