Odd "jam"...any ideas?

[JWG223]

Equipment:

-Noveske 10.5" chrome-lined upper
-Surefire 556-212 suppressor
-H2 buffer
-Mil-spec USGI spring
-Mil-spec BCG + Colt "Gold" extractor spring, no O-ring
-Lancer L5 AWM magazine
-PMC XTAC M193, 5.56 Optimized 70gr, MK318 (I did not see which did "jammed")

Situation:

Semi-auto (rapid) fire with a clean weapon well-lubed with Froglube CLP, ambient temperatures 87*F and humid but without rain.

Malfunction:

-Bang-bang-bang-bang-bang-bang-deadtrigger.
-Inspection (visual) immediately revealed carrier out of battery by roughly 1/4".
-Magazine released (was locked in).
-BCG retracted easily using CH and locked to the rear.
-Back of loaded round visible in chamber, almost completely (lacking 1/4" or so) seated in chamber. Primer un-dimpled.
-BCG allowed to close, easily fully chambering the round. Trigger pulled. Round fired and ejected. Magazine re-inserted, and new round chambered. No further failures to eject, feed,extract, or lock back on empty.

Question:

-How the hell did the round strip from the magazine, fail to chamber by only 1/4", and not have the extractor snap over the rim, and yet easily chamber and fire afterward (not an out-of-spec anything) with a clean weapon that was very well lubed using nearly all-new USGI spec springs and an H2 buffer?

 

[#1bambam]

Well it is a AR...Just sayin.

 

[JNieman]

Is it like a stupid-stiff extractor spring or something?

Nothing unusual on the well-cycled brass?

The only thing I can see is that if the extractor isn't allowed to hop the rim easily enough, it'll stop the bolt... but I haven't had my coffee yet, either.

 

[JWG223]

Is it like a stupid-stiff extractor spring or something? Current military spec issue for MK18-A4

Nothing unusual on the well-cycled brass? Not that I saw

The only thing I can see is that if the extractor isn't allowed to hop the rim easily enough, it'll stop the bolt... but I haven't had my coffee yet, either.

That's what I was thinking, but I can drop the bolt from about 1.5" and it will snap over a chambered case's rim. Much less SHOOTING the rifle.

 

[bigjakewelch]

How many times has it malfunctioned. If it was just once than it can be any number of things. Ie.. A pice of brass from one of the other rounds got under the extractor and wouldn't let it snap over or you had a weird 3 point bind, or the round was deformed by a few thousands and the initial force wasn't enough to get it to chamber, or your mag surged up and the rounds rose up and slowed the bolt enough that the extractor didn't have enough force to snap over the case rim, or....... I could go on for ever. When a semi auto is fired it is an extremely violent action. There are things going on that only a high speed camera can catch. If it was a one time occurance then I'd say, no big problem. If this malfunction happens frequently (once or twice every range session) then I'd get it looked at by a gunsmith. Just my $0.02.

 

[JWG223]

How many times has it malfunctioned. If it was just once than it can be any number of things. Ie.. A pice of brass from one of the other rounds got under the extractor and wouldn't let it snap over or you had a weird 3 point bind, or the round was deformed by a few thousands and the initial force wasn't enough to get it to chamber, or your mag surged up and the rounds rose up and slowed the bolt enough that the extractor didn't have enough force to snap over the case rim, or....... I could go on for ever. When a semi auto is fired it is an extremely violent action. There are things going on that only a high speed camera can catch. If it was a one time occurance then I'd say, no big problem. If this malfunction happens frequently (once or twice every range session) then I'd get it looked at by a gunsmith. Just my $0.02.

It was only this one time, and probably has to do with the suppressor overgassing it, if I were forced to guess. My best guess is that the funky Noveske lower caused the round to somehow leave the magazine and hit something before luckily finding its way into the chamber, and the bolt's force was diminished by such that it didn't fully go into battery. That's the best I have.

 

[JNieman]

Oh, it's a Noveske lower, too?

Nevermind, I'm out.

 

[olivs260]

Try sticking it in the freezer for a couple hours.

 

[JWG223]

Oh, it's a Noveske lower, too?

Nevermind, I'm out.

Yep. Bag of snakes junk. It is what it is, though, and out of spec NFA items are HARD! to dump.

 

[dixiejarhead]

Check your bolt rings for wear. Sometimes they protrude and catch enough to allow this to happen. Happened yesterday at the range to a buddy of mine's 10" noveske upper with AAC M42000 on it.

 

[Richard in LA]

It sounds like, at least to me, that the flash hider/mount was installed incorrectly.

 

[jgreco15]

Small piece of dirt? Broken off carbon build up that slowed the bolt/BCG enough to not fully go into battery? A super strong extractor spring would do this over and over, not just once. As Dixie said, could be bolt rings. Is the gas tube straight? I've seen bent gas tubes that put friction on the BCG as it went into battery. Is it possible to limp wrist a carbine?

 

[JNieman]

inb4 "shits where it eats"

 

[Vanilla Gorilla]

Out of spec chamber.

 

[doc ace]

Try sticking it in the freezer for a couple hours.

It's a one time deal. Maybe bad cartridge or like you've previously stated over gassed by suppressor. Also check the bolt rings to make sure they all the gaps aren't lined up


Maybe youre limp writing?

 

[pangris1]

Novekse sucks now??? Mine has been boring in its reliability, accuracy and modularity.

 

[JNieman]

Novekse sucks now??? Mine has been boring in its reliability, accuracy and modularity.

OP had major problems with his equipment being out of spec, and Noveske **** on him when he asked them about it, iirc.

On top of that, I've seen a handful of other anecdotal instances of lower receiver troubles in very recent time.

Welcome back.

 

[slogoat]

IIRC noveske didn't want to work on his noveske lower / Daniel defense upper hybrid?

OP had major problems with his equipment being out of spec, and Noveske **** on him when he asked them about it, iirc.

On top of that, I've seen a handful of other anecdotal instances of lower receiver troubles in very recent time.

Welcome back.

 

[dixiejarhead]

Interesting that the same malf occured on my coworkers gun yesterday and come to think of it it was a noveske lower as well. Upper was 10" with AAC M42000 can. Must be overgassing. Switching to a one piece bolt ring may help the issue.

 

[slogoat]

My 10.5 inch noveske runs great with or without my m4-2000. I do run a bcm bcg, though.