Just curious.

I keep a magazine loaded with defensive rounds, but would always remove them and replace with range ammo for recreational shooting.  I'm curious if loading/unloading multiple times can adversely affect the their reliability?

I heard some one say that if he ever chambers a round and unloads it prior to firing, he will trash the cartridge.  Different scenario, but it made me curious about the above.

Of course, the obvious solution (that I only now came up with - heh!) is to simply use another magazine for recreational shooting.   But still curious to see if there is a generally held opinion on this.

Thanks in advance -

Loading them and unloading in a mag won't do anything bad. Clambering and then ejecting over and over can cause turtlenecking or whatever the cool guys call it. That can be a problem.

 

Setback.

Setback is indeed unhealthy... Chambering/unchambering the same round a lot is not a good idea.

I generally toss any round that has been chambered and then ejected into my bucket of blasting ammo for the next range trip.

The stock answer is, 'Yes, chambering and re:chambering a round will eventually set the bullet back into the case.'  However, if you're careful, and chamber that top round very gently; or, if you learn how to tilt the muzzle up and let the extractor claw slip in behind the head then you might be able to chamber and re:chamber the same top round over and over again for (I would say) weeks, perhaps even months before it becomes wise to finally shoot it off.  (I've done this more times than I can count; but, then again, I know how!)  

I'm curious.  You're using the same magazine over and over again for everything?  What for?  As a general rule of thumb - but especially if your compete in pistol competitions - you should have as many as 8 magazines for each semiautomatic pistol that you own.  (I've seen many competitors show up at matches with a lot more!  The 8 is just what they wear on their belts.)  

To directly answer your question:  Yes, repeatedly loading and unloading the same magazine will cause the spring to wear out at an accelerated rate.  Keeping a magazine fully loaded - or almost fully loaded as I prefer to do - will NOT wear out a mag spring; but repeatedly compressing and decompressing it will.  



NOTE:  It just hit me like a, 'falling brick wall'!  You said that you keep your pistol loaded with, 'defense rounds' - Yes!  In which case you should absolutely positively own, at least, one more magazine.  NOT because you might need to reload in the middle of a CQB pistol gunfight; but as insurance against any sort of MAGAZINE FAILURE from the one magazine you're, now, relying upon to keep you safe.  

(That's not a smart thing to do!)  

Do a google search on the pressure increase of setback on a 9mm.  



That alone should stop you from chambering rounds repeatedly.

yep.  keep an eye on them.

You can rotate the top one down farther in the magazine (after inspecting it for length).  This way you're spreading the chambering stress over the whole magazine.  

If you're a reloader you can use a kinetic bullet puller to slip the bullet forward a bit.  Reseat and recrimp and you're nearly good as new.

The worst bullets I ever saw for loosening were the Remington Golden Sabers.   They had a driving band at the base of the bullet and a slimmer upper portion before the ogive started.  So you had much less friction with the jacket.  (The harder jacket I guess dictated that design for the trip down the barrel)

I do this for my CC, and buy new ammo every few months once they start to look a little beat up. Loading and clearing every time I leave/return home wears on them

if keeping it fully loaded doesn't wear out the spring (dubious, but lets grant it) then why would you not keep it fully loaded? Is it for match reasons or do you do that with a carry pistol too?

With USGI AR mags, it can be very difficult to seat the mag on a closed bolt when fully loaded. Many prefer to load 28, rather than 30, to resolve this. With many of the newer magazine designs this isn't an issue.

On old Gen 1 Glock mags (all polymer), a fully loaded magazine would swell, and become difficult to seat and not drop free/become very difficult to remove from the gun. Many police departments created policies against fully loaded Glock mags. Newer Glock mags with the steel skeletons no longer have this issue, which makes loading below capacity unnecessary.

Keeping it loaded doesn't wear it out, repeated compression/decompression does. I believe what he meant was that it is advisable to not repeatedly load and unload the magazine you carry or otherwise rely on to defend yourself with. In other words, dedicate a magazine that has been vetted as functional to your defensive application (carry, nightstand, etc.) by keeping it loaded with defensive ammo and separate from other mags that are loaded and unloaded frequently like the ones you shoot with at the range.

ETA    There was an episode of Gunfighter Cast (link) earlier this year where John McGregor had a great discussion on magazine basics.

Hm, learn something new... So he is basically using an anachronistic TTP?

Depends. I still do it with USGI AR mags.

Some very knowledgeable people still load below capacity pretty much every type of magazine... They probably have a reason for doing that. I don't claim to be an authority figure. My rule of thumb though, is without a system specific reason for loading below capacity to avoid a problem, load to capacity, and be consistent.

 
First, I'd like to thank the several people who've already done such an excellent job of answering this question.  These answers are right in line with my own thinking; but there's more.  I've been using and carrying guns for a lot of years.  During this time I've learned a few basics about magazine springs, as well as what to expect from different semiautomatics.  (Sometimes from different guns with the same model number.)  

In the past 11 years I've had 3 failures to extract over a FULLY LOADED magazine.  That's too many failures!  Fully loading a magazine can cause top round problems.  The pickup rail is subjected to increased pressure, and it may cause the slide to short stroke.  Ejection can be impaired, too, when the first +1 loaded case bangs into the fully loaded top round as it starts to eject.  

My uncles, the men who taught me how to  handle firearms, were veterans of both the South Pacific Campaign, and Korea.  Because of exposure to sand and grit, lack of proper cleaning, and the numerous pistol malfunctions the Corps experienced whenever these pistols were loaded up, they weren't allowed to fully load their 1911-A1's, and had to learn to live with only 5 rounds in the magazine.  To the 1940's and 50's Marines' way of thinking their pistols were, 'last ditch' weapons; and their 1911-A1's had to be utterly reliable.  I learned this precaution from them; and, for a fact, it's kept me in good stead throughout my entire long life.  

Another reason, 'Why' I don't fully load my pistol magazines is because it's quite possible for me to carry a pistol for months on end with the same three magazines.  If I compress the springs all the way down and give them no room, 'to breathe' I risk forcing the mag springs to take too tight a set.  I tend to be very gentle on my guns; and, like my uncles, I place reliability ahead of magazine capacity.  (I spent most of my life carrying only 6 or 7 rounds in a pistol.  I mean, hell, if I can't get the job done with 13, 15, or 17 rounds then, maybe, it's time for me to take up archery!)  

In the past decade I've had numerous years when I've gone through better than 10,000 fired rounds without any sort of mechanical pistol-related problem.  I never use full magazine +1 pistol loading - Never!  Neither would I gamble with my life by going even further and +1 loading anybody's polymer frame pistol.  It's rare for one of my semiautomatic pistols to FTFe, FTE, or experience a mag spring problem.  

To my training as well as my experience and way of thinking, stuffing a pistol as full as you can get it is just plain reckless and stupid.  If I need a pistol then I need it to absolutely positively, 'go bang!'  Everything else is a secondary consideration.  6 extra rounds on top of a total of 39 isn't going to do me any good if I'm lying dead and bleeding on the ground with a jammed up semi-auto in my hand.  

I carry Hornady's 135gr Critical Duty and tested it by rechambering the same rd over and over until I got measurable setback. That took 25 rechambering's to achieve .01" of setback. I will now rechamber the same CD rd 15 times before rotating it to range ammo.
Tomac

Thanks for the information, everyone.  Very much appreciated.

I'll start keeping a magazine loaded with defensive rounds, and use that as my defensive mag, and use another mag (or two) for the range, and mark them accordingly.

I generally don't load pistols all the way, especially ones that need much stress to load the last round.  It just seems to make sense that if you have to force the last round in, something isn't right, regardless of how many rounds it should hold.  I have a Glock 30SF that can load ten .45 ACP on a good day, and only with a good amount of pressure - its been that way for months, so I'm thinking it is not going to "break in".  On the other hand, I have an FNX .45 Tactical that has no problems with the full 15 rounds.

i keep an excel spreadsheet with all my firearms SN as well as ammo, and magazine I have on hand. on the spreadsheet is also a list of carry/home defense guns I keep loaded and ready to go with premium ammo. i rotate the ammo in those guns every 6 months. i also rotate rounds in the magazine if i unload the weapon for range use.