First I am located in the mountain west, so the best crops the deer I hunt have to eat are alfalfa, and even that is scarce. I've shot many mule deer and 3 whitetail, as well as many elk. I process all myself and generally expect under 40 pounds from a young buck and 50 pounds would be a pretty good size whitetail buck. I think maybe 60 pounds from a large muley buck is what I've gotten, but it's been a while so wouldn't be dogmatic about that. My wife likes consistent size packages of meat, so I weigh every single package when I process and therefore I have a pretty darn good idea what I'm getting. This year my 125" rack white tailed buck gave me 37 pounds which includes the plastic bags. I agree with a previous poster that 25% of live weight is about what you'll get for meat. I have found the 25% rule to apply fairly consistently to elk as well, and I grew up on a cattle ranch where I'm pretty sure 25% is what they used for beef as well, but that's a little tougher to judge since a lot of beef is bone-in. In my experience a lot of guys over guess how much meat they have, part of the excitement of making a harvest I think. I used to over guess, until I started weighing it.