I've cut up about 25 cow elk and around 15 bulls in the last dozen years or so. I'm pretty particular about my meat and trim way more than a butcher so my yields are lower but this is about what I've seen for yields.
Cows 100-150lbs A yearling cow shot in August would be at the lower end of that and a old cow shot in November or December seems to be at the upper end.
Small bulls 175-200lbs
Big bulls can be 250+lbs
One of the bulls I shot this year was the biggest elk I've been next to. The neck muscles were massive. We boned out the front shoulders, the back straps, and the neck meat all in separate bags. There was less than 5lb difference in weight between the bags. Obviously I can't weigh them now but I'd have made a pretty sizable wager the neck meat was over 30lbs. The chunks from each side were as heavy as the back straps. When someone says 5-7lbs of neck meat from the usual elk I would say they are damn close to the average. This was no average elk though.
I would say the yield from that elk, which was pretty heavy already gutted, should have been at least 30+lbs more considering he most likely added beef or pork fat to get to the 116lbs. His yield should have been at least 1/3 of the gutted weight IMO. Elk do vary a lot in body composition and the time of year but a 500+lb live weight cow is pretty big. I wouldn't be surprised to see 150-175lbs of meat come off that elk because it's pushing the size of many raghorn bulls around here.
