Some of these replies are IMO not boneless meat, but with the bones in. The largest certified live weight moose went, as I recall (my moose book is 600 miles away...), about 1700 lbs (1695?) at 5 years old. They did not weigh it after that, as it was getting cranky and hard to handle as it reached its full maturity. This was a Yukon/Alaska (largest subspecies) from Interior (largest within the subspecies!), bottle-raised at the Moose Research Center on the Kenai Peninsula, Alaska , with no lack of food or stress from winters and predators.
Now, the larger the animal, the higher the percentage of boneless meat, which is unlikely to go over 50% for a 1700 lb animal and possibly slightly under that. Bone in will add at least 100 lbs on the larger animals. A "yearling" bull moose will likely be closer to 40% boneless to live weight.
I will stipulate that I believe that bulls, which reach their maturity at about 7, may well get heavier than that pampered, but documented! live-weight 5 year old on record. I've seen some with the physique of a Hereford bull, which I wouldn't put money on not to exceed the documented record! And of course they are individuals, with different genetics, even in the same area. The last bull I shot a few miles south of here was tooth-aged at 7, and the cow with him was bigger - the biggest one I've ever seen. I guessed her live weight (at 30 yards) to be in excess of 1,000 lbs - and that's as tight as I'll put it! OK - I personally think she went 1200 to 1300 lbs - but I'm not claiming that.
By the way, I have killed 21 Alaska bulls, mostly on the Kenai, several in Interior, and two here in NWArctic. For a couple years I hung out as an occasional volunteer at the Moose Research Center - and even those guys that had the advantage of working with moose every day and weighing them (trained to step on the scales) said they were lucky to be able to guess a moose weight plus or minus 100 lbs. before scaling them. So there's a bit of salt involved here with anyone's "live-weight" guesses. Only a scale tells the unadulterated truth. And that's a difficult thing to get a wild moose to agree with! Dead or alive.
I have weighed the boned meat from my largest and smallest bodied 15 month old bulls ("yearlings"). 333 and 270 pounds, respectively. Both were taken on the Kenai, about 5 miles and 3 seasons apart. The largest one had 3 inch stubs for antlers, the smallest one had 16 inch spikes. Go figure! I have weighed the hinds (bone in, off at the knee and without the pelvic girdle) from two bulls that I figured were probably both 5 years old. One was from the Kenai, the other from here in NW Arctic. 110/ 111 lbs for the Kenai bull, and (IIRC) 95 and 97 for the Noatak bull. Just under 100 lbs, anyway.
