That’s laughable, sad actually. A 7mm RM is very effective for elk. I often use a 280 REM, same bullet smaller engine, works very well.
There are some gun writers that have said a 338 Win Mag is the best elk cartridge. Clearly the elk they hunt have a layer of kevlar under their hide.
I know a very long time and successful outfitter, he prefers his cow elk hunters use a 243 over nearly any new to them magnum. Because they are not afraid of it and hit where they aim. There is a lesson in there the “internet” often misses.
I listen to those that have killed a few box cars full of elk. Most of those sort are not posting all over, but occasionally will offer their thoughts if asked.
Been a part of 3 elk and 1 buck kill in the last 5 weeks. 2 cows (7mm RM and 270 Win) and a nice bull (270 Win). All dead with the first shot, one was shot a second time because he had not fallen over yet. The Buck was with a 223 REM, one shot and done fairly quickly.
Small sample, but 3 of the 4 were with moderate cartridges and died as fast as the one hit with the magnum. A 6.5 CM would have worked just as well. Bullets used, in order, were 150, 140, 130 and 77 grains. Bonded, cup and core, and a mono bullets were all used.
The 3 most important factors for a quick kill, in order, are placement, placement, and placement.