Storing loaded magazines
A look at a new magazine compared to one that has been loaded for six months. Not much difference. I’ve always operated under the assumption that what’s actually hard on magazines is how many times they are compressed not if they’re stored loaded or not.
October 27th, 2009 at 10:28 am
We spent a lot of time covering fatigue and failure of materials when I was in school for my engineering degree. All metals fall into one of two categories (or 10 categories for you programming guys): those with a fatigue limit and those without one. Metals without a fatigue limit, such as aluminum, will fail at some point if they are cycled. The more extreme the stress applied to the metal when it is repeatedly flexed, the sooner it fails.
Metals with a fatigue limit, such as steel, can be flexed effectively forever, as long as you don’t exceed the fatigue limit, and don’t do anything to the metal to change the properties of the metal. So, with a well designed magazine, you can leave it loaded forever and the spring will continue to function normally.
However, if you store that loaded magazine in a condition that would allow the magazine to rust, or expose it to very high temperatures, you would change the properties of the metal in the spring which could cause the magazine to no longer function properly.
http://en.wikipedia.org/wiki/Fatigue_limit
I did enjoy the comments to that thread though. It’s so funny to see people that believe they know better than anyone else, even when the test is just reproducing results from decades of science. I guess the science behind material fatigue just doesn’t FEEL right.
October 27th, 2009 at 10:42 am
I’m not terribly worried about the spring in my AR mags… I’m concerned about the feed lips. I’m using some polymer mags (not PMAGs) and I’m wondering if the feed lips will crack or stress if they’re fully loaded for too long.
October 27th, 2009 at 2:31 pm
I just took my Mossberg 590 apart and wiped it down. It had been loaded with 8 shells for close to two years. I noticed that the spring (Wolff +10%) was short enuff that I could hear it slide back and forth in the tube.
Still works but it may be time for a new spring?
October 27th, 2009 at 5:31 pm
I think there may be a hidden agenda behind this myth: If you store your magazines unloaded, then your gun is unloaded, and not ready for action when needed. This is just what the anti-gun crowd wants.
On the other hand, if your magazines are loaded, you are ready to fend off zombies/thugs/stormtroopers, which makes the anti-gun crowd nervous.
I have heard enough stories about WWII magazines taken out and shot without problems that I think the whole thing is BS. What I haven’t heard is a single story about somebody who had a magazine loaded for a long time who experienced a malfunction.
Not saying it hasn’t happened, but I need more proof than the “It seems reasonable, so lets err on the safe side!” assertion that I keep hearing.
October 27th, 2009 at 7:31 pm
While I appreciated the effort of the thread parent, he really took his lumps from the “know-it-alls” that he tried to help out. I learned two things, #1: I believe the chap is correct about loaded mags and #2: no good deed goes un-punished.