Eh… on paper, sure. But we have to play a game of cudbeshudbe to pretend there’s a real difference in the field. Everything in North American COULD BE cleanly harvested with any of these three, but it’s up to the individual hunter to decide whether they think a given round SHOULD BE used, according to their personal standards. 280rem is a 7-08 burning ~10grn more powder to run ~150fps faster… 5% more speed, 5% more momentum, 11% more Kinetic Energy…
It seems, also, you’re looking to put your son on deer, which simply does not necessitate a bonded bullet. Deer don’t benefit from spending extra on bonded bullets unless they’re doing things they shouldn’t be doing. For example, I’ve found the 105 Berger Hybrid traveling around 2800fps to be one of if not the fastest deer anchoring bullets I have ever used… just a cup and core BTHP… Are NAB’s better? Eh, not really. They don’t open as much, internal damage is less, deer travel more, and they just tear up the hide on the far side more.
And towards the future, personally, if I pick up a long action hunting rifle, I want mine chambered for magnum cartridges. I don’t find any advantage for a long action to hunt deer, rather I’ll use a 100-140grn bullet over 30-45grn powder in a short action 6-7mm cartridge and live happy the rest of my days in the deer woods. If I’ve increased game size beyond what is within the bounds of my personal “cudbeshudbe” with a short action, it means I’m after game which is large enough and with rare enough opportunities - or hard enough opportunities to manifest - AND in sufficiently unfamiliar territory that I don’t want to risk any undue tracking distance, such that I simply don’t bother with standard boltface long action cartridges. Personally, for larger game, I’m taking a short action magnum like 300wsm or 6.5 PRC or long action magnum like 300wm/PRC or at least 7rem mag. I’ve played the games pushing 280rem AI and 284 Shehane to crazy pressures to match the 7rem (or almost so), but in reality, I’d rather be carrying a 30cal magnum with enough case to reach out and hammer these true big game animals.