Name the malfunction

I don't know what to name it, but it appears that your rifle might be way over gassed.

Really fast carrier speed can induce these kind of malfunctions.

Probably the front of the bullet is diving down as it is being stripped and the bolt
is just pushing the case head up.

Magazine would be the first thing to swap.

It’s called a bolt override. Bad mag is the culprit

roostercogburn98 said:

It’s called a bolt override. Bad mag is the culprit

Click to expand...

OK, what causes this?

Brass over bolt. Usually magazine related. Round is able to pop free of the magazine and get the ass end up over the bolt head.

Buy some lancer mags




Personally I like the 20 and 10 round mags for most things

Earnhardt said:

OK, what causes this?

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Feed lips worn or bent and unable to keep the top round in the mag as the bolt is in rearward motion during extraction/ejection. There’s a quick way to clear it without tools(about 5 seconds) but hard to describe. I’ll try:
1) pull back hard on charging handle. It’ll move less than an inch.
2) reach up through magwell and touch the front of the bolt with a finger(usually middle finger) and press backwards as hard as you can
3) while holding rearward pressure on the bolt in step#2, smack the charging handle forward with your other hand.
4) Observe round falling out and make sure it clears the weapon.

This is also a great way to smash the finger which holds the bolt in the weapon action, so be careful. I find this method to be faster and more reliable than mortaring the rifle.

"The death jam". Base over bolt, I've seen them so bad it took three guys and a pair of pliers to get it undone.

The fact that there's so much open space up there for it to happen is the biggest flaw in the Stoner design IMO.

Earnhardt said:

OK, what causes this?

Click to expand...

Others covered it, but USUALLY feed lips are starting to widen and it can’t reliably hold the round in. It is classed as remedial action and not immediate action. With some practice, you can usually clear it with minor issues. Sometimes it will take some time and that is why is listed as a remedial action stoppage.

TacosGigante said:

Yeah. That plus the BCG being wedged into the buffer tube, preventing me from breaking the gun open had me rethinking the wisdom of the design.

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This is not an actual jam, but a picture I took years ago to explain what I meant to someone. The fact that this is even possible, to get a whole cartridge up there, means things should be different.



Another minor grumble of mine is the ejection port. Yeah I know it's kept small to keep crap out of it. But you get simple little issues that could be fixed with the flick of a finger, but you can't get it in there!

Can you test thumping the mag in the bottom and see how easily the round pops out compared to newer mags? I am be interested since I have some pmags that are a bit loose but still no malfunctions from them.

Also clean dirt under the magazine lips, it might play into this effect. Normally the extraction grooves on cases take a lot of that away but some harder dirt might still remain.

Explanation around 3 minutes in for vid 2.

cas6969 said:

The fact that this is even possible, to get a whole cartridge up there, means things should be different.

Click to expand...

Interestingly, this can’t happen with 6.8 SPC, Grendel and all the other calibers with a base wider than 5.56

When I mention "three men and a pliers", that was after all the proscribed methods of clearing it were exhausted. When it finally came out, the round was bent at near a 45 degree angle.