I tend to "shoot out" the ammo in my mags first, and go on from there while at the range.
As for ammo "longivity"..... I finally fired out the last of a box of .25 cal I had since '81 just a couple of years ago. Nary a problem.
Good "tip" about the top bullet's potential for slug letback. Comes to follow that giving a mag that little extra "ooomph" to click it in place, will, if the slide/bolt is home, put some pressure down and back on that bullet.
Only load mags when the slide/bolt is open would go a long way to preclude that from happening. On the other hand, the guns I have stashed around the house do not have one in the tube, so I typically shove the mag in with the slide home.
Carry guns? I load with slide open before going out the door, as I carry with one in the tube.
GG
Fanatics of any sort are dangerous! -GG-
Which part of "... shall NOT be infringed..." confuses you?
Well now, aren't WE a pair, Raggedy Man? (Thunderdome)