Now, bare in mind at the time of the story I'm about to type, I had a .257 Roberts and a 7 mag and I'd just gotten the 7. My buddy had just gotten a BAR in 300 win mag and his other rifle is a Browning BLR in .308. It was our first trip to the Guadelupe mountains in New Mexico. We thought we needed the magnums for the long ranges out there, I guess. And, I did take one about 350 yards across a canyon that year with the 7.
We walked into the only little store in miles and miles around in a little hole in the wall called "Queens". There were a bunch of hunters in there for lunch, they were serving great burgers. Everyone was chatting and the owner had some ammo on sale and asked what we were using. I told him, Larry told him, the room erupted in laughter. "Whadda want them cannons for, the elk here are illegal ya know.?" Turns out one of the guys was using a .257 Roberts, a couple had .308s, and there was a .30-30 toter. ROFL! I think Larry was offended, but I mean, really, what do ya need a belted magnum for on deer???? It did the job, though. I've shot one muley with it and four white tails and it is over-kill. Since I got my .308, that's all I hunt with anymore.
When I bought the seven, I was thinking .280 Remmington. I really like the .280. I like 7mm bullet selection. But, I reasoned, if I'm going to get a long action rifle in .280 anyway, why not go with the magnum? I can always load it down. If I go elk hunting some day, I might want more power with heavier bullet loads in the 7. I handload, so ammo cost is not a consideration, but the 7 is widely available and the .280 is a bit more rare. So, I stepped up to the 7 and I don't really regret it. I like having it, knowing if I wanna tackle elk someday, I have the gun for the job, not that the .280 or my .308 couldn't kill an elk, but I may only ever get one elk hunt in my life if I ever get that. So, I hang on to the big gun. Besides, everyone needs one magnum rifle in their collection, just ain't complete without it. I can see the same logic in .30-06 vs .300 if you're more a .30 cal guy.