As a random aside, a Bren gun magazine will take 30 rounds, but you had to put 28 in as it did occasionally jam if you had 30 in...always wondered abut that. But no, as has been noted, compression per se does not "wear" a magazine. Seems a bit silly to have a loaded magazine lying around and not emptying it by fire though.
Currently...Sako TRG 22, Model 29 .44 Magnum, Beretta M9 9mm, Beretta Neos, Colt AR 15 x 2, VQ 17 M2, Anchutze .22 hornet, the ultimate 10/22, LOTS of M1 Carbines.
"Beware of the Man with one gun...he probably isnt into guns enough to be safe with it".