To my understanding, the hunting bullets are the problem. Most hunting bullets don't want to open up below 1800 fps. So if your 7mm elk/moose bullet arrives at 1700 fps, it just drills a 7mm hole in your elk.
This will NOT put your elk down. He may run off, or wander off into the deepest darkest hell-hole he can find before he dies or not. You may not find him for days, if ever. Personally, I harvested a cow elk with a healed-over hole in her heart and one lung. Clearly, bullet damage.
Loosing an elk or moose will not be a lot of fun for you. So why do it??
The 7mm WSM
is a great cartridge for target shooting at 1000m or farther.
It drills holes in paper with the best of them. If this is what you want to do,