Is it OK to keep my M&P mags loaded

[100$bill]

If I keep my M&P 9mm mags loaded will it damage the magazines eventually? I haven't not had any FTF in a couple years now, but am a bit concerned I may be wearing down the springs.

If it does cause eventual damage, how many rounds can I keep in the mags of a full size or a compact and still have long term dependability?

 

[Crazy Ed]

Keeping mags loaded will not damage them. Mag springs are cheap and can easily be replaced if you do end up with some kind of feed issue. Mag spring issues are more gremlin related rather then being caused by keeping mags loaded.

Stay safe!

Ed

 

[carbuncle]

OK to keep loaded, it's repeated loading and unloading that wears springs out.

 

[darksideemt]

The officer that taught my gun class just recommended not doing the full capacity +1. He said it would help to do a full load in the mag and then if you want one in the chamber rack it but don't add one back in the mag. His reasoning was more for the base of the mag, which he said he had seen a couple fail from the pressure being in the mag for a long period of time. It made since to me and 15 rounds instead of 16 isn't that big of a deal to me.

 

[Murdock]

The officer that taught my gun class just recommended not doing the full capacity +1. He said it would help to do a full load in the mag and then if you want one in the chamber rack it but don't add one back in the mag. His reasoning was more for the base of the mag, which he said he had seen a couple fail from the pressure being in the mag for a long period of time. It made since to me and 15 rounds instead of 16 isn't that big of a deal to me.

This should not be an issue for any properly designed and well constructed magazine. Your call. Mine are used full capacity plus one.

 

[The Sarge]

Modern pistols like the M&P are primarily designed for military/LE use. Neither of which has the time to worry about magazines or go through rituals of down loading or rotating. Quality magazines and their springs are designed to remain loaded to full capacity over a long period of time with reliable functioning. Topping off the magazine after chambering a round is proper and is included in the magazine design. Bill

 

[Martya]

Sarge got it right. Google Hooke's law of elasticity. Assuming proper raw material choice and proper manufacturing process, and as long as it has not exceeded its strain and elastic or compressive limit, the spring will continue to function as designed in its application theoretically forever.

Working within these limits, basically the only destructive force would be the atmosphere eroding the material. Raw material contaminants and abuse outside the functional intent can reduce the life of a spring also.

 

[dannybot]

I usually keep mine either loaded or unloaded....

 

[federali]

Forever Magazines

I was once given a loaded 25 auto magazine (probably a baby Browning) continuously loaded for over 50 years since WWII and I was recently given a Browning Hi-Power magazine loaded about 30 years ago and forgotten. Upon removing the rounds, both magazines functioned just fine and I detected no weakening of the springs.

However, I generally don't top off my mags if a fully loaded magazine cannot be easily inserted under a closed slide.

 

[chuck s]

I've fired both M1911 and P'08 magazines last loaded 50 years prior. No problems. Fired M16 magazines loaded 30 years ago. (Amazing the stuff in old foot lockers!)

Full magazines seem to load fine in closed slide/bolt weapons for me. Only "advantage" in downloaded magazines is less ammo.

-- Chuck

 

[enfield]

If I keep my M&P 9mm mags loaded will it damage the magazines eventually? I haven't not had any FTF in a couple years now, but am a bit concerned I may be wearing down the springs.

If it does cause eventual damage, how many rounds can I keep in the mags of a full size or a compact and still have long term dependability?

Follow the manufacturer's recommendation. They know better than us.

 

[falconman515]

Follow the manufacturer's recommendation. They know better than us.

What are S&W recommendations on this?

Reviving this thread since it basically asked the question I came here to ask and didn't want to create another thread.

I just bought an M&P9 CORE and have 5 total mags ... I keep them full (I'm in CA. so full is 10 rounds).

I was wondering if this was okay to do at all times on these springs or if it causes issue over time?

 

[Jiman]

A properly made spring in a static state (full or empty) doesn't cause spring fatigue. Its the work a spring does over time that causes 'wear'.

New springs generally take a set after a short period of time, which is normal so comparing a used but good spring to a brand new one isn't a proper comparison. The normal recommendation is to fully load a new mag a few days before you use it for the first time for proper function.

I know this is the M&P forum but the same question gets asked regarding whether they should keep the hammer cocked on a 1911 or not all the time and it's perfectly fine to keep it cocked.

 

[richg204]

i keep mine loaded at all times no problem its a spring let it do its job

 

[fdw]

All mags in all my guns are fully loaded and there is always one in the chamber.

 

[Alpha Sierra]

A properly made spring in a static state (full or empty) doesn't cause spring fatigue. Its the work a spring does over time that causes 'wear'.

New springs generally take a set after a short period of time, which is normal so comparing a used but good spring to a brand new one isn't a proper comparison. The normal recommendation is to fully load a new mag a few days before you use it for the first time for proper function.

I know this is the M&P forum but the same question gets asked regarding whether they should keep the hammer cocked on a 1911 or not all the time and it's perfectly fine to keep it cocked.

This most excellent post should be a sticky at the very top of each gun forum in the world.

Very few firearm topics generate so much myth and misunderstanding as springs do.

 

[Old cop]

FWIW the mags for my Glock 23 have been loaded long before I retired in '97 and continue to function absent any problems.

 

[Muss Muggins]

Loading mags to one less than capacity for a self defense gun, especially for those spare mags intended to be used for reloads, can be very helpful in accomplishing a tactical reload (some rounds fired, slide in battery, round in chamber, but you've found cover and want to "freshen up). A full mag is much more difficult to seat properly.

 

[Nakanokalronin]

Fully loaded all the time +1. I've only encountered a few guns that needed the magazine hammered in when fully loaded. One was a G30SF weather it was the 9 or 10 round magazine. I kid you not when I say that I had to hold the slide like a handle and hammer the butt end of the gun with the fully loaded magazine to get it to seat. Once seated, it was like dragging two files across each other when trying to chamber the top round. I even cut off coils in the mag springs and it was still the same. Weather someone's G30SF also does that or not, mine did and became a terrible firearm design in my mind. It was that or Glock was trying to fool me into thinking those were actually 9 and 10rd magazines. Loading them was a major pain as well. I left them loaded minus a round for a month and I still had to use all my strength WITH a magazine loader to get the last round in.BTW,I never hammered it with a round already in the chamber. Long story short, I got rid of that abomination ASAP.

Second one was a SD9VE. It wasn't nearly as hard to seat as the G30SF, but it was enough that I left it at 15+1rds. It's no big deal since it's the same size and capacity as a G19 at that point. The 16th round was easy to load, but the mag wasn't easy to load on a closed slide.

That's all I can think of off the top of my head. Besides those two, the fully loaded mags on my semi-auto handguns are easy to insert and kept that way until I shoot it. The repetition of compressing and decompressing the spring causes fatigue, not keeping them loaded.

 

[M&Pmeister]

"Eventually"? Yes. Whether that should be a concern to you is debatable.

The fact that a magazine spring will "break in" and take a set isn't exactly a good thing... technically. That means the spring steel has undergone some plastic deformation and lost some of its free length. Good thing is, this is not a self-perpetuating problem. As the spring free length is reduced, so is the spring rate, albeit slightly. This reduces total force the spring will exert when compressed, accordingly so is the stress it sustains. At some point, there will be an equilibrium point where the stress is less than what it takes to induce further plastic deformation. That's the spring "taking a set".

A good magazine design balances between competing goals:

1. Minimizing weight and bulk
2. Reducing stress/wear on other parts of magazine (lips, for example)
3. Maximizing service life

If a magazine spring takes a set, it could be that the engineer intended for the above mentioned equilibrium point to be reached quickly. You can, of course design a magazine spring that have so much capacity that it will never take a set, but then you add weight and bulk... or mfg cost using higher-performance material. Good design means a magazine spring is just long/strong enough to perform well in its expected service life.

So... should you worry about all this? Depends on how anal you are, I suppose. Magazine springs rarely fail catastrophically, so you can always change them out when you start noticing performance problems. More than likely, a quality magazine in civilian use will outlast you and your children combined.

Personally, I use them to the full capacity... in general. On lower capacity mags like my Shield 40 and Bodyguard, which only holds 6 or 7rd, by golly I'm using every last rd of capacity I paid for. OTOH, downloading a 20rd mag to 19 probably isn't gonna make a whole lot of difference tactically. Not a bad idea especially if that 20th round is a bear to push in.

BTW, I doubt anybody can load/unload a magazine fast enough - or often enough - to frequency-fatigue a typical magazine spring. To do that, you'll have to exercise the spring at high frequency and duration, which a normal working magazine will never experience.


Suffice it to say, if I have an antique German Luger .45, I probably would not load the magazine full and leave it sitting.