Re: 7mm or .30
FWIW, moose are not the same breed of cat as elk. One would think that moose are tougher than elk but the opposite is true. An elk's will to survive is astounding where as moose bleed a little and give up, even on a single lunger. You single lung an elk, kiss him goodbye. This is the exception and not the rule as I have seen a few moose that seemed to have 9 lives as well as elk that have been single lunged and been collected after a brief tracking job. But for the majority, you make a moose bleed, they tip over. You one lung an elk and its off to the next county.
All that said, I also believe that a 6.5 can kill elk cleanly. I also believe that it is VERY important to select ONLY perfect shots for elk where as some lesser willed game can be shot with a slightly less than perfect shot. Before you crucify me, I am not talking about taking bad shots on any species, but elk require (IMHO) no less than 100% perfection due to their strong will. A bigger bullet with more mass and energy can in some cases be more forgiving when the perfect circumstance changes when the bullet is mid flight. When it comes to elk, dont fool around. Hit them with ALL you can comfortably handle. If all you can handle is the 6.5 sweedish mauser, than by all meens, use it. If you can handle the 338 RUM or LM, then leave the 6.5 in the safe.
Long range shooting is a process that ends with a result. Once you start to focus on the result (how bad your last shot was, how big the group is going to be, what your buck will score, what your match score is, what place you are in...) then you loose the capacity to focus on the process.