[ExGeeEye]

1. Under ordinary conditions, how long does ammunition last? How old would it have to be before you just disposed of it somehow?

2. Would you keep ammo in a mag, or would that fatigue the spring?

[osagebowman]

I’ll put in my two cents on that one. A darn long time given reasonable storage conditions, the old .50 cal and .30 ammunition boxes are great for storage, as are the 37mm shell boxes.

I’ve shot lots of ammo of WWII-Korean vintage, more recently .22s from a collectors estate that were from the 50s and 60s half boxes or in bags.

I rotate when I can but some I occasionally find give rise to questions of the age, especially when there’s a price on it.

My swiss ammo is from the 60s, one box from the 70s. I understand the last batch that came in is from the 80s.

Going to order up another case of that. GP-11 is fine match grade ammo that was regular issue to the Swiss Army.

Like I said, my two cents, your groups may vary. :-)

[300winmag]

I'd start to distrust ammo over 50 years old. Of course if the case neck is cracked, the powder has already oxidized. The biggest problem with old ammo that otherwise appears good is erratic performance. This will still be safe to shoot, but will have wide variations in velocity. Another symptom is the appearance of duds, which indicate primer problems. One failure-to-fire should disqualify the entire lot of ammunition. GI ammo that has been hermetically sealed all that time has the best chance of still being usable.

Long-term storage of fully-loaded magazines is still the subject of debate. I've kept .45ACP and 5.56mm in fully-loaded magazines for three years as a test. No problems with either. But it's best to cycle both ammo and magazines to keep things fresh.

What is known is the stainless steel magazine springs in GI 30-round M-16 magazines will eventually "take a set". The result is not enough spring pressure to feed the last few rounds. The Army recognizes this, and recommends turning in the magazines for new springs when this happens. If it happens to you in a firefight when you need those last few rounds, you may have some problems.

Chrome-silicon springs are "set resistant", but will rust, so need more attention. "Extra power" springs also bring you an extra margin of spring power as the springs age. As time goes by, I've been replacing my GI springs with Wolfe extra-power chrome-silicon springs (some mags are over 30 years old), and newer anti-tilt magazine followers. I've even replaced the springs on my IBM carbine, in case I ever feel like buying some ammo and shooting it again.