I think that the following military covers may be of interest to some members.
30 year ago, the Army held a major exercise at Gagetown, NB, from 01 Jun to 6 Jul 1981. For this occasion, 5 military post offices (MPO) were opened (MPO 81, 103, 111, 112 and 115).
Philatelic covers bearing the logo of RV81 and cancelled the first day of the exercise were issued. I have 3 complete sets, each with a different stamp.
In one of the cover, I also found a note providing detailed information on this military exercise and MPOs. It is shown below.