Thursday, April 05, 2007

Boomsticks: Download errors.

The Anarchangel takes on the fallacy of downloading magazines, and notes the two main exceptions: AR15 and Glock magazines. I can definitely concur on both of those (the only feed failures I ever had with my personally-owned Glocks, other than my G30's strong dislike for semiwadcutters, were caused by topping up full mags after chambering the first round.)

Add to the list the famous Wilson 47D eight round mag for the 1911. The combination of follower design and tube length will cause the spring to die a premature death if left loaded to its full eight-round capacity for any great length of time. Some folks rotate their mags; after several rebuilds, I just started using my 47Ds as seven rounders and haven't had to replace a spring for five years (although I probably should do so soon, if only on general principle)...

Let me add some tips for what to do with damaged mags, such as AR mags with spread feed lips or AK mags with feed-disrupting internal burrs: When I'm engaged in a practice session and I encounter a mag with issues, I set it aside in a pile. At the end of the session, I relocate the pile to the nearest trash receptacle after pounding the defective mags flat with a hammer, lest some penny-pinching fool rescue them in an attempt to potentially risk his life in the name of saving a few bucks. I consider it a public service.

(H/T to Unc.)


Chris Byrne said...

Yaknow Tam, I've never had that problem with the 47D. I've left mags loaded for six months (I always cycle them at least twice a year) without any problem.

I DO replace the base plate on all my 47ds with the low profile steel pad, but I wouldn't think that would make a difference.

Any time I DO have a spring problem with any mag, I replace the spring with a Wolff and pretty much never have a problem again.

Tam said...

Turns out that this is the reason the FBI changed the mag spec on the Professional Model from 47Ds to 7-rd Metalforms. FWIW.

Jeff said...

Thats good to know, I usually leave my 47Ds full, I'll have to get some wolff springs for them soon.

FWIW, I have not had a problem with them yet but its not the type of thing I really like to leave to chance.

Chris Byrne said...

Oh I'm not saying it doesn't hapen; just that I've never had that problem.

I've updated my original post to relect this, and also to note this isn't a question of qualit of springs, it's one of design limitations.

The fact is, 1911 mags were designed for 7 rounds, and compromises have to be made to bring them up to 8rd capacity. These compromises leave much smaller tolerance for error, or out of spec parts, and put greater stresses on the springs.

Desertrat said...

If the spring steel in a magazine spring is decent material, properly alloyed and heat treated, it doesn't matter how many years it stays compressed. The caveat is that the steel not be stressed beyond its yield point. Same for recoil springs.

Nor should it matter how many times the gun fires or the mag is reloaded.

Disagree? You must not have ever thought about the valve springs on your car, then. They cycle some 1,000 times a minute when off-idle; 60 minutes to the hour, last I heard, and it takes around 3,000 hours or thereabouts to get to 100,000 miles. 1,000 x 60 x 3,000 = A Bunch. And when they're parked, half of the valves are compressed; some are fully compressed. Think "Museum cars", or cars in storage where springs can remain compressed for years--but they fire up and run.

Any problem results from low-quality material used in the springs that are then provided to those who make pistols and their magazines.

I tested a 50-cal. ammo can's worth of pistols, a few years ago. They'd been packed away, mags loaded, for some forty years. They all functioned perfectly: A Lilliput, a Woodsman, two old .30 Mausers, a .30 Walther, a P-38 and a 1912-vintage 1911.

Not that I've ever messed with ancient stuff, ya understand...

:), Art

Kim du Toit said...

Yeah, I once fired some 1911 mags which had been left loaded sonce 1945, and they all worked fine -- even the old ammo fired flawlessly.

And I swear by Chip McCormick 8-round PowerMags. They have always worked perfectly, and I've put (rough guess) about 10,000 rounds through each of mine. They are all, always, loaded up to 8, except the one in the Springer which has 7 (because the 8th is in the chamber).

People who talk about metal "flow" in spring steel are ignorant of metallurgy -- because "flow" in spring steel is almost measurable in geological time units (as is glass).

Paul said...

2500 rounds through my Glock 23, with about a third of those being from a 13+1 state. Never a FTE or FTF.

Anonymous said...


I've put probably 100k+ through my nine Glocks (3 23, 2 23C, 2 33, 1 29, 1 30) over a decade or so, before I sold the last. It happens.

Don't believe the hype.


Jay G said...

Heck, I popped off two or three M1 carbine 30 rounders (with 32 or 33 rounds in each) that had been sitting, loaded, in my grandfather's damp basement for at least 25 years before they were moved to my dad's dry attic for another 10.

All mags worked fine, all rounds worked fine.

'Course, that was at the range, not with my life at stake. And you just know Mr. Murphy waits for such occasions... ;)

Hobie said...

I've found that most military mags for the M16 do require "down loading". 18 for the 20 rounder, 28 for the 30 rounder. But let's remember, these are made by the lowest bidder and the age of the springs seems to matter not at all.

An acquaintance of mine once worked on the development of a 50 round magazine for the M-16 which would actually work with the full 50 rounds so it isn't an impossible task. BTW, that mag was never adopted because you can't get in the prone with that thing.

I've never had any other mag that wouldn't work full up if it would work at all, provided the springs were new enough. I've used some Colt mags that were left loaded for 10 years without problems.

Will said...

I have several Officers .45 ACP, no govt size. This model has problems stovepiping the last round while feeding. Early on, I put MagPak spring and follower kits in all my mags. They increase capacity one round. I have NEVER had a feeding problem, and they are always loaded max. Same springs since about 1990. Absolutely no problems in classes and matches. Oh, BTW, these are all OEM Colt mags.

Marko said...

You know, I've come to conclude that if the frakkin' gun was designed to eat hardball out of seven-round magazines, maybe that's what you ought to feed it.

Come to think of it, I can't remember ever having a failure to feed out of any of my full-sized 1911s when fed such a diet.

Gewehr98 said...

Can I have all the 30-round AK mags that you previously crushed and shit-canned simply because they had a few burrs inside?

Tam said...

"Can I have all the 30-round AK mags that you previously crushed and shit-canned simply because they had a few burrs inside?"

No, but you can have the ones I spent a couple bucks on as replacements. They work flawlessly. ;)

Matt G said...

Art, the main difference is, those pistols that you pulled out of the ammo can that were fully loaded had designer spec magazines.

JMB never designed an 8-round magazine that fit flush in a Government Model.

We're pushing the specs a little. I can be done, but we have to accept that we're going to go through springs a little faster.

FWIW, my relatively inexpensive Chip McCormick PowerMags haven't taken a set yet, even though I'm terrible about leaving 'em loaded for months and years at a time.

Matt G said...

At the pistol match the other day, I lost count, and overloaded a 20rd AR mag.

It took me three hard tries to seat it before I figured it out, flipped out the round, and went back to work. Embarrassing. Potentially dangerous. THAT's another reason why I shoot matches, and recommend that others do, to. (...Tamara...)

Jonathan said...

"Marko said...

You know, I've come to conclude that if the frakkin' gun was designed to eat hardball out of seven-round magazines, maybe that's what you ought to feed it."

I have to agree. It seems the 1911 crowd has a lot of problems with finding a magazine that works.

Porta's Cat said...

I had an AK mag with a small dimple (on he inside) that hung the follower.

Took a drill and drilled a hole a bit larger than the dimple in the side of the mag. Then took a file and filed the inside burr (from the drill) down flat and clean.

The mag worked fine after that, as the dimple was now gone, and replaced by a small hole.

A lot for work for an $8 magazine, but it can be done.

Is the mag now worthy of fighting zombies during the apocolypse? It has a hole in it, so maybe it is best for strictly range work and not for Red Dawn. But, I would bet you a 6 pack of beer it would be fine, as it continues to function well.

Desertrat said...

I don't try to cram eight rounds into a GI mag. But I do change them into eight-round mags. :)

I grind a slot across the back of the mag, at the bottom. I cut a "Zee" from the spring. I grind off the follower's leg that trips the slide lock.

They have been as reliable as any other magazine, since I was first shown this trick in 1981. Weak spring or no, the eighth round has always fed as properly as the first.

And they're easier to load. :)