Do You Under-Load Your Magazines?

I load AR 30-rounders to 28 or 29 to make it easier to seat on a closed bolt. Don't have a problem with other pistols or rifles though so I load them to capacity.
I think the general consensus on spring fatigue is that it isn't affected by leaving it compressed, just by cycling (loading and unloading).

I load my XD40 to 11 instead of the full 12. I have heard conflicting info on spring fatigue and figure better safe then sorry. Besides, if i need more than 11, that is what the other two magazines are for.

I think the general consensus on spring fatigue is that it isn't affected by leaving it compressed, just by cycling (loading and unloading).

Click to expand...

Exactly.

I'm not a metallurgist or anything, but I was under the impression that partial compression was worse for the spring than full compression. I'm sure someone here has the definitive answer.

I've got a lot of 30 round AK mags, but I tend to load em to 20 rounds just because that's the number of cartridges that come in 1 box
I empty one box into my right hand, load the mag, shoot it, repeat.

Same deal with my PT111; I load it to 10 because I can just slide the styrofoam out of the cardboard box for two rows, and dump 10 rounds into my hand at once.

I don't have any spring-stressing concerns or whatever. It's just practical for me.

'm not a metallurgist or anything, but I was under the impression that partial compression was worse for the spring than full compression. I'm sure someone here has the definitive answer.

Click to expand...

Well we've had many metals experts chime in on this and the consensus has always been that it is compression-extension cycles, not steady compression, that is the problem. Full or partial compression mattered not.

But it's one of those "9mm vs .45" things so it will go on forever

The spare in my holster I load to full. The one in the gun is down one bullet from full.

I keep hearing about how Glock magazines leave the spring "over-compressed" when filled to capacity and inserted in the gun, but I've yet to encounter any problems.

I replace the springs every other year, though (and use ISMI +10% springs). They do seem to "wear out" faster than single-stack mag springs, but that's just the nature of a double-stack pistol mag.

The constriction at the top really limits the speed at which the rounds can come out. Thumb rounds out of any double stack magazine, and they'll sort of flop out. Thumb them out of a single-stack magazine, and they go flipping through the air if you're not careful.

I have always under-loaded by two rounds because of concerns about spring life but it looks like I am in the minority. I guess I'll start topping them off.

No.Full loads in main and spare mags for my Glock 36.
I'll wear out before the springs,probably.

How many post a year do we read on this site about bad mag springs? Seriously?

I fill 'em up.

Same deal with my PT111; I load it to 10 because I can just slide the styrofoam out of the cardboard box for two rows, and dump 10 rounds into my hand at once.

Click to expand...

I don't know about you, but my PT111 only has a 10rd mag. Unless you're talking about "combat loading" or topping it off (10+1), in which case, I only carry 10rds. That 11th one always gets lost somewhere.

California underloads them for me, considering my 15round Beretta Mag has a chunk of plastic on the bottom that limits it to 10rounds.

Just AR mags with 28 rds

I under load them because I don't like shooting 30 rounds in one sit and I like to practice my mag changes.

I underload them with my rifles as I rarely feel like shooting a 20 or 30 round group.

I'm not a metallurgist or anything, but I was under the impression that partial compression was worse for the spring than full compression.

Click to expand...

I am no metalugist either, but I am a shooter, and have some tactical knowledge. It would be foolish to unerload a magazine in the great majority of self defense carry. You are shortng yourself on one or more bullets that could quite possibly be the ones that would save your life. If you are using a firearm that either cannot be loaded reliably, or cannot function reliably, with magazines loaded to full copacity - get a new gun that functions correctly. If the srpings in your mags are failing - get new springs. Then carry loaded to full capacity. If you are ever involved in a shootout, and a legal issue somehow is how many rounds you fired, you will always be able to tell if your firearm/magazines were loaded to full capacity. More iportantly, I would rather have that one (or more) extra round(s) in my gun at all times. never know when it will be the magic bullet.

All the best,
GB

I load my 14 rd .40cal mags to 12 and 13 on account that that's how many rounds come in a box of Golden Sabers.

I load to capacity my .45 auto mags on account of not having that high a capacity in the first place. The sad fact of carrying the .45 with one back up clip is that I have roughly has as many rounds to put down range before I go empty as when I'm carrying the .40

i guess the good news is that I shoot patterns that are twice as tight with the .45 than with the .40. So that's gotta count for something.

For home defense i keep 10 in my 15 round mag. When i carry i carry with 15+1 in the chamber. Ruger p95 if you were wondering. Hopefully i'm getting a 1911 or a snubnose (.357) soon. 9mm is fine but i like those calibers better.

Nope. Max capacity, all of them, all the time. Home defense and carry guns are kept with fully loaded/topped off mags and one in the pipe. If they won't function reliably like that, I'll find a magazine or gun that will, but so far that isn't an issue.

As Glenn said, you never know when that one or two rounds would be the difference between saving yourself or your loved ones and bleeding out while hearing your wife/children scream their throat horse in the last moments of their lives.

For defensive weapons, if they don't work properly, get it fixed or get it gone.

I used to. I know for a fact that that last little bit of spring travel often does greatly increase spring fatigue. I have even marked some magazines that were only under loaded to compare with others of the same age because I had heard the argument made a lot that its the compression and uncompression of the spring and the amount of compression has no impact.
One round crunching the spring as far as possible can have a big impact, and I have proven it to myself.

So in a larger capacity magazine it is a consideration.

In CA though many firearms are already limited to 10 round magazine. That is already lower than desired so loading to 8-9 is not a valid option.
One less in a standard capacity auto holding around 15 rounds is fine. Loading a rifle mag to 28 or 29 instead of 30 is fine.
Loading a 10 round to 8-9 is not fine. Giving up 5% ammunition is not such a big deal, but greater than 10% is.


I have also seen this appear with tube magazines, especialy shotguns. The spring is much more likely to bind or wear out when loaded and stored at max capacity than if loaded one round short.

They do in fact last much longer, and wear out much more evenly when they are not compressed to thier minimum size. However I have seen people argue otherwise.

So do you have laws on capacity? If not then it can be a valid consideration. If you however do have laws on capacity I wouldn't short change yourself by a significant percentage of ammo.

Common sense should tell you it makes a difference and is having an impact on the spring when that last round is 5x harder to put in than all the previous ones. You are really smashing that spring on some magazines.

Put me in the camp that underloads AR mags by two. But those are the only mags that I underload.

My SAIGA I underload, my Lee Enfield I do not.

My little Colt (.22) is underloaded but the Glock is not.

The .22 is strickly a target pistol, reloading time isn't an issue. The Glock is our 'bedside' pistol and should it be needed reloading would be an issue. As Dad often says- it depends on situation and terrain.

Selena

I don't know about you, but my PT111 only has a 10rd mag. Unless you're talking about "combat loading" or topping it off (10+1), in which case, I only carry 10rds. That 11th one always gets lost somewhere.

Click to expand...

Mine hold 12. I don't know if the 12 round mag is a new thing (I bought it 1 year and 4 days ago, woo!), or only on the mil pro, or if you just happened to get one for the 10 round only states. Dunno.