This may sound gross, but I guess they never expire (or at least the old types didn't back then).
Years ago I was in New Mexico, traveling with my ex, when our car broke down. We ran out of money & were stranded. We found a friend who allowed to stay in his camper for the time being.
He had quite a few military foods, they were kind of old, all in tin, like sardine cans.
I ate turkey w/ stuffing, macaroni & Cheese and a meat loaf one, all were actually pretty good, the macaroni & cheese I must say was awesome.


My brother hikes & camps a lot, (hiked the appiliachian trail & the such) and has eaten a lot of similar foods. Not sure if they are the same as the military ones or not, but they are all in bags & look just like those.
He says that they are good. There are a few that he doesn't really care for but he's not too fond of those certain food in "real" form either so he really can't say anythign about those. He says they are better than you think, and better than carrying around a lot of weight & are nutritious.