[NightSleeper]

Springs in magazines are designed to be compressed. Hence, "springs".

A lot of what you hear even today applied to the springs used in decades past. For example, I often read of soldiers in Vietnam being coached to only load their 20-round M16 mags with 18 rounds to prevent jamming.

But that was long ago. These days, as long as you aren't using a really old gun or magazine, most of these issues have been fixed. You can leave your magazines fully loaded without fear of jams or problems. But if you are weary about it, you can always underload you shotgun magazine by one or two shells and leave the spare nearby to load up when the SHTF.