I've seen this happen a couple times now. While handling a full 30rnd mag the first round was dislodged and this seemed to trigger a chain reaction which resulted in a the entire contents dumping. Yeah, basically 30rnds being launched all over the bench. These are Colt USGI mags. Any known causes? I'm thinking the mags may be too full. My kid has a habit of loading them until the Lula can't stuff another round in.
Thanks --RR

Yeah possible overload,Also check the feed lips for spread...Oh yeah and teach your kid how to count to 30.....J/King..[;)]...UNDERDOG

Yeah, him learning to count to 30 sounds like a REAL GOOD idea...lol. Is there any "rule of thumb" dimension between feed lips?
--RR

I've see this happen with dirty mags.
The follower gets stuck and doesn't allow the spring to hold pressure on the rounds.

Interesting explanation though it appeared the rounds were ejected under full spring tension. They literally launched vertically out of the mags. I'll definitively be checking them out for cleanliness though. --RR

edited to add- The more I think about your explanation, the more sense it makes. His gun jammed a couple times and when I went to clear it... the problem was NOT a jammed round or casing because chamber was clear. I thought the bolt was "sticking" due to gumming up with oil and carbon (he'd probably fired 180 rounds min at that point). It didn't dawn on me at the time but I bet the follower was stuck, the next round didn't feed, and that resulted in the bolt locking back..... damm, I gotta check that out when I get home. Thanks for the help!
--RR

If they came strait up under pressure it sounds like the lips are spread.

See my edit above. Also if anyone knows the appropriate gap between feed lips I'd like to know. I haven't had any luck locating a copy of the MIL SPEC.
--RR

Beats me.  The obvious is out of speck magazine lips.  But I couldn't help myself....



LOL!  How many twisted ways could someone interpret that sentence?

Sly

Just trying to see who all is paying attention today.

[:D] I was thinking the same thing but this not being the "general discussion bunch" thought best to keep my mouth shut..... lol

Top round will be on the [i]right[/i] with a fully loaded USGI 20 or 30 round magazine.  If you're using the Lula it'll be on the left as you're working the loader.  

Putting 21 or 31 in will usually merely jam the rifle, not dump the contents.

-- Chuck

ok, what effect if any would this have on function of the magazine?


I'm thinking an overloaded mag cannot even be inserted unless the bolt is back. And if it is back. How does the extra round jam the gun? A double feed when the bolt is released? That's the only scenario I see happening.
--RR

Another vote for spread feed lips. Had two Orlites, a generic steel 20 rounder (all looked normal) - as well as several USGI mags with visible cracks at the rear of the feed lips that did this.

Again... anyone with MIL STD or known dimensions/tolerance for feed lip gap and configuration?... please speak up. --RR

Take a new mag and put a set of calipers over the feedlips. Measure the width. This will be an in-spec mag.

Measure the one that dumped rounds all over (I would assume if it was dumping rounds that there would be a visibly noticeable difference in size). Compare it to the new mag.

BTW, loading 31 rounds into a mag often time creates too much spring pressure and the bolt can no longer strip the round out of the magazine.

Uh I have had this happen to withone of my unmentionable mags. Its a crappy mag and I know that but still it was odd. I heard this popping then pting pop pting and the mag was ejecting 223 all over the place. I think its the width betwee nthe feed lips or a spread mag or something.

You'll have to try 21 or 31 rounds in your own rifle to determine how it jams the weapon.  The extreme pressure on the feed lips will commonly cause a top round failure to feed.

Overloading and dicking with the magazine springs on the followers were the two reasons we loaded 18 rounds per magazine in the 1960s.

Once we got all the magazines fixed and started getting ammo on clips we loaded them to 20.

Inserting a full magazine in the rifle with the bolt closed is a standard procedure.  The magazine is designed to function this way.  There are often problems with 10 round "post ban" magazines 'cuz the magazine makers are paranoid about an 11th round getting in there.

If you're having problems with USGI 20 round magazines feeding the first few rounds, or the 19th and 20th are hard to get in, check the spring on the follower against a good magazine.  The spring is likely on the follower wrong, or the follower is on the spring wrong -- I'm never sure which is on which.  [;)]

-- Chuck

I've seen this happen once.  I picked up a loaded 30 once and seen that the first spot weld (?) was no good.  I then slapped it agianst my hand I witnessed about half the mag empty.  I laughted my ass off!  It wasn't my mag.

I had a Ramline that would do that like every 3 loadings (it was usually a little warm when it would do it).  I wonder what happened to that mag, probably stuffed in a box during one of many moves.

If it hasn't been suggested already, remember to check for cracked feed lips.

Take the suspect mags apart and brush them out thoroughly and apply some dry lube to their insides.

CJ