Clark's right. Those are 50ft targets for marksmanship training with 22s. In the early '80s I was a young E-5 assigned to an Army ROTC instructor group. We had a 50ft indoor range and had a couple of boxes of these stacked in a corner. I expect ours were leftovers from the '50s - we didn't use them; we were using modern guns to train the cadets and used the reduced range qual targets.
Happy New Year, all!
Eric