True or myth?

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Infamous

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I was told by an old timer to carry with 1 less in the magazine. This helps keep the mag spring strong. Anyone else do this/heard this? I hate sacrificing a round in an already low round sub compact.
 
Old myth; alive and well in the US Army. Never heard the "it keeps the mag spring strong" part though. I was always told "makes it feed more reliably".

At any rate, it's false. It MAY be true with a single type of magazine or weapon from a long forgotten era though. I find most myths that don't die tend to have at least a toe in planted in reality.

Also, with some mags (The ever popular PMAGS, for example.) it's possible to cram in a 31st round... which screws everything up. Your individual experiences may vary.
 
Infamous said:
I was told by an old timer to carry with 1 less in the magazine. This helps keep the mag spring strong. Anyone else do this/heard this? I hate sacrificing a round in an already low round sub compact.
Click to expand...


Now, a myth. May have been true in the past and I was told by many people in the military over the years the spring would become weak.

Now, springs are relatively cheap and you can buy them + 5 or +10%.
 
My preban USGI AR mags are loaded with 26-28 rounds. With a full 30 rounds in the mag they don't lock in as easily.
A few Marine friends over seas right now told me they only load something like 28 rounds in their mags as well. Can't remember the figure but it's not capacity.

My CCW is +1 in the chamber.
 
At work we always kept 28 in the AR mags for that reason, I always thought it sounded like a good idea but o well.
 
JCV said:
My preban USGI AR mags are loaded with 26-28 rounds. With a full 30 rounds in the mag they don't lock in as easily.
A few Marine friends over seas right now told me they only load something like 28 rounds in their mags as well. Can't remember the figure but it's not capacity.

My CCW is +1 in the chamber.
Click to expand...

Do you load the mags with the bolt locked back ?
I never have a problem loading my mags with 30rd rounds . If the bolt isn't locked back I just have to smack it in .
 
If this is the case, then I'm packing 9 into my 8 round Shield Mag, maybe that will finally loosen the sucker up. Cripes I need a forklift and a tire changing machine to press down the spring.
 
Springs of the modern era only wear out from repeated expansion and contraction (i.e. loading and unloading). Keeping a modern spring contracted will not wear it out prematurely.

As far as feeding. Probably depends on the gun/mag.

StevensMarksman
 
Springs dont wear out during static compression - e.g. fully loaded or empty mag. If you stretch them out - i.e. apply tension or tensile force, you will damage them - the technical term is called "creep" - a permanent deformation of the structure. Now, cycling a spring - e.g. from a loaded mag to an empty mag and repeat - you will induce "fatigue" - thats the technical term. This is when cracks start to develop and elongate; we are talking at the microstructure level here. If the cracks elongate enough, the spring will "fail" - crack or split. That generally doesn't happen when we are talking about gun springs, but with enough cycles and time - enough cracks form to reduce the overall springy-ness of the spring and they what you would call wear out - not a technical term.
 
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Myth. Mag springs only wear out by going through compressions, decompression cycles. Compressing it fully doesn't wear it out at all. The only reason to do this would be if your gun has reliability issues on a full mag, or possible for your spare mag so it's easier to lock into the gun during a hasty reload. Since modern semi-auto pistols don't usually have issues with topped off mags, I'd say carry completely full.
 
Actually there may be some science behind the "myth". F=kS where force=spring constant * distance .... the spring constant is a constant at a set of environmental conditions (temperature for ex). While temperature itself is not a direct factor for changing the k ... it does this through increasing the length of the metal through expansion. How much this affects k is dependent upon the material. An increase in temperature would lower k, and lower the force.

Of course this is for an IDEAL spring ... and, of course, the change in spring length is very small over temperature gradients.

Maybe in very specific instances, unique situations, the myth holds true. But generally the change in k is very very small ... and has no effect.

I've had issues with M16/AR15 feeds but that has nothing to do with the magazine only...ammo, feeds, and mag combined can create issues.

https://www.youtube.com/watch?v=RfI6QDy9Xpk

Feed ramp video ...
 
PaulR said:
If this is the case, then I'm packing 9 into my 8 round Shield Mag, maybe that will finally loosen the sucker up. Cripes I need a forklift and a tire changing machine to press down the spring.
Click to expand...

I imagine the shield mags are close to the ones that came with my m&p9c. If so, take the mags apart and use a dremel tool to grind off the 'legs' from the bottom of the follower.

Sent from my DROID BIONIC using Tapatalk 2
 
Generally speaking, fully loading a mag should have no ill effects as far as spring life is concerned. I remember Colonel Cooper addressing this issue. He said that he left a few 45 ACP mags fully loaded for several years with no problems. Although mag springs can withstand this sort of abuse I don't recommend it and doubt Colonel Cooper did this on a regular basis.

Spring tension is another problem. As mentioned, some AR mags are not reliable when loaded to full capacity. This tension makes seating the mag a problem and can also affect the functioning of the weapon due to excessive friction on the BCG. This is something you have to deal with on your own with your weapon. The biggest concern is too much spring tension making it difficult to seat the mag. The next problem is too much friction (due to spring tension) on the slide which can cause feeding and cycling problems.

The solution is simple, shoot the gun. If you can seat the fully loaded mags reliably with the slide in battery and the gun cycles, your problems are most likely non existent. I have experienced problems with excessive spring tension in S&W 9mm M&P ten round mags. I could not reliably seat a fully loaded ten round in a pistol with the slide in battery.

I called S&W and complained only to find out that I had the "new and improved" mags. So much for S&W customer service. In this case I had to trim one coil off of the mag spring and trim the bottom of the follower to open enough space in the mag to fit ten rounds with enough space left over to allow for the further compression of the rounds when the mag is inserted into the pistol with the slide in battery. Seating the mag should be relatively easy, if it takes excessive force you have two choices; load one less round or modify the mag. I prefer to modify the mag to get it to perform the way it was designed.
 
Gammon said:
Generally speaking, fully loading a mag should have no ill effects as far as spring life is concerned. I remember Colonel Cooper addressing this issue. He said that he left a few 45 ACP mags fully loaded for several years with no problems. Although mag springs can withstand this sort of abuse I don't recommend it and doubt Colonel Cooper did this on a regular basis.
Click to expand...

How is it abusive to leave a magazine loaded for long periods?
 
Its a myth that has some truth to it. Although the reasoning has little to do with the spring wearing out.

I have used handguns that did not do well seating a full magazine if the slide in battery. You had to really slam the mag home HARD to get it to seat. I had this problem with some 10 round Glock 17 mags.

I have also used handguns that did not reliably feed the first round after the first shot if the mag was full. The gun in particular was a mid 90s Kahr P9 Covert.
 
The basis wasn't spring fatigue, it was the USGI 30 round mags would malfunction when full. So units started loading 28 or 29. I'm amazed that this has carried down all these years.

Some units would put a tracer as #25 or 26, is that still done?
 
Gammon said:
Generally speaking, fully loading a mag should have no ill effects as far as spring life is concerned. I remember Colonel Cooper addressing this issue. He said that he left a few 45 ACP mags fully loaded for several years with no problems. Although mag springs can withstand this sort of abuse I don't recommend it and doubt Colonel Cooper did this on a regular basis.
Click to expand...

Unless I'm at the range and have just fired off my expensive carry ammo, the magazines that I use for carrying are fully loaded. These three 1911 magazines have been loaded that way for at least 5 years. The magazines that I used previously were loaded for about 10 years. They all worked perfectly.

I've got some Glock 17 mags in my safe that have been loaded for almost 20 years. They still work, too.

Leaving magazines loaded is no more abusive to the magazine springs than leaving your car parked on its tires, with its weight supported by its springs.

Loading and unloading magazines is more abusive than just leaving them loaded.
 
hurley431 said:
Old myth; alive and well in the US Army. Never heard the "it keeps the mag spring strong" part though. I was always told "makes it feed more reliably".

At any rate, it's false. It MAY be true with a single type of magazine or weapon from a long forgotten era though. I find most myths that don't die tend to have at least a toe in planted in reality

Also, with some mags (The ever popular PMAGS, for example.) it's possible to cram in a 31st round... which screws everything up. Your individual experiences may vary.
Click to expand...

Fit 32 in a thermold 30 rounder. No issues there [smile]
 
garandman said:
The basis wasn't spring fatigue, it was the USGI 30 round mags would malfunction when full. So units started loading 28 or 29. I'm amazed that this has carried down all these years.

Some units would put a tracer as #25 or 26, is that still done?
Click to expand...

Some people swear by it; but, they're few and far between. It's honestly easier to keep count (or an ish estimate) than people think. I've seen squad leaders (especially weapon squad leaders) load their mags full of tracers in order to facilitate directing the fires of the weapon systems under their command. Things like 240's and such.
 
garandman said:
The basis wasn't spring fatigue, it was the USGI 30 round mags would malfunction when full. So units started loading 28 or 29. I'm amazed that this has carried down all these years.

Some units would put a tracer as #25 or 26, is that still done?
Click to expand...

I load 28 in my USGI type mags because with 30 they generally need to be smacked to seat on a closed bolt.
 
Another trick with AR mags is to take a look at what side the round is feeding from.

If its on the right, then there are an even number of rounds in the gun, from the left and its odd.
One way to confirm you've chambered a round, other than a press check is to see if the side that the mag is feeding from changes after you drop the bolt.
 
MYTH.

There are some times when loading one less is helpful, like with these 10 round limit mags, they're so tight that if you load some to max capacity they're more likely to malfunction. but it has nothing to do with the spring wearing out.

Also you don't want to overload any mag beyond it's stated capacity. Sometimes you can jam one more in but that's just asking for a malfunction.
 
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