Matt,
I would agree and disagree with your comments. Here is why.
In temperment, moose are generally MUCH less "driven" then elk are. BY that I mean that they have a much more relaxed way of life then elk do in their temperment. Yes, moose can get a bit ****y and when they fight they can get very serious about it.
When an elk spooks however, it will often run, and run and run and run and within minutes its in a different sip code. This can happen and often does on an elk that has been shot but the shot impact did not contact any major support bones or nervous system.
A moose on the other hand, generally will not run far. It may hit cover but then generally will hole up. They may in fact wait for you to come and make a charge on you but they generally will not cover the ground that an elk will when injured. This is what I mean by the fact that they are easy to hurt.
If you next look at the lung capacity of a bull moose you quickly realize, as you have witnessed that if you put a bullet or several bullets through the lungs, it will STILL take some time for the animal to actually drown in its own blood. This time can be greatly increased if the bullets impact is low in the chest without hitting the heart or near the rear of the lungs. They just have a HUGE lung capacity.
Elk on the other hand seem to have much higher heart rates then moose so an elk shot though the lungs will generally bleed out faster but they will also generally be running while they die and they generally run into the nastiest cover they can find and run until they can no longer run from blood loss.
IF a moose had the drive that elk did, they could cover miles with even good shot placement.
I have shot elk with clean shots through the chest cavity and the bull hardly reacted to the shot but he fell over dead within 20 yards after several seconds.
I have also seen elk shot perfectly behind the shoulder that took us on a mile long hike.
I have also shot moose with my 7mm Allen Magnum and 160 gr Accubond at 3500 fps. First shot at 200 yards put the bull on his nose but he instantly regained his feet trotted 50 yards and stopped. Second shot was behind the shoulder, no reaction but the shot was certainly lethal, third shot was actually at the bull as it charged my guide. This shot impacted at the crook of the neck and broke the spine of the bull and he fell for the last time.
My point is simply this. A marginal shot on a moose with a lesser caliber will generally result in the moose hitting the first bit of cover and he will stop there offering either another followup shot or just take time for them to pass.
A marginal shot on an elk will result most often in a long training job at best and often a lost animal simply because once they start running, they seldom stop.
A moose may take a long time to die, that is for sure. But they are not hard to kill. Most people often panic because the animal does not appear to be effected by the shot and keep shooting when in most situations, the animal is dead, its just a matter of time but because the hunters have enough time to empty their rifle on the moose, they feel they are not using an adequate weapon for moose. That is hardly the case. They just need to realize that the critter they are hunting has a HUGE lung capacity, HUGE blood supply and unless you hit major support bones and often take out the nervous system as well, you will not get much reaction from a moose when you shoot him.
ALso consider that a 500 yard moose is a HUGE target. Easy to hit. A 1000 yard moose is still a huge target. Just the nature of moose, unless they are spooked, they seldom move around much at all. Slow, big, will not run much after being shot, perfect long range targets even with moderate chamberings.
My recommendation for to use a 300 RUM would work perfectly well in any situation you recommended, vastly superior to your 7mm loading for moose so not sure what your arguement really is directed towards to be honest. Still, I would never feel under gunned with a 7mm magnum and a quality bullet for any moose hunting, even for 1000 yard hunting.
For elk however, and their likelihood to cover alot of ground after a solid hit, I would recommend something alot larger, again, for over 800 yards, at least a big 30 cal magnum and for 1000 yard elk hunting a larger 338 magnum would be recommended.
Your example of your experience with the moose proves my point, you had PLENTY of time to get additional shots into that moose. Just because he did not react to you do not think he was not dead on his feet. If your expecting to take a moose off his feet with any rifle with a clean chest impact, you will be very unimpressed with every chambering out there. It simply does not happen that often without hitting high shoulder or spine.
Most moose that fall to the shot are in fact spined. This is because most of the time, the hunter does not realize how low the spine location is compared to other big game animals because of the large dorsal fines making the hump on the mooses shoulder. They shoot for high shoulder and more often then not spine the animal instead.
had you hit the bull on the first shot in the high shoulder and he fell on his nose, you likely would have had a different opinion of the mooses toughness.
My point is simply this, his lack of reaction to the shots has nothing to do with toughness, but more to do with sheer size more then anything else.