Strange one

[Walkalong]

I have an AR in 300 BLK that started off as a 5.56. After converting it I tested a lot of things by way of various powders and bullets (All supersonic). I blew one primer in one test batch. No others in the batch showed any sign of pressure, so I wondered if it was bullet setback. Doesn't matter, I blew a primer, and stopped with that combo. Haven't used that bullet since, but it is a favorite of 300 BLK shooters. (I don't remember if I ever found that primer - hint)

So, many, many, many rounds later my nephew was shooting it Sunday afternoon. Several bangs in it just went click. Hmm..... Inspected it and the remaining rounds. The round from the chamber showed no firing pin indent. Not good. Tried another round, and click, no bang, no primer indent. Tried to take it apart and it didn't want to open up from the rear, and I had to pull the front pin to get it apart.

I took The BCG apart when I got home and nothing was broken, but the BCG doesn't go into the upper quite far enough. OK, maybe the carbon is built up too bad to go completely into battery. Cleaned it up real good and the same thing. Put the front pin in, go to close it, and the BCG binds against the top of the lower above the buffer tube, refusing to let it close. I get out a new BCG and they are both the same length with the bolt back, but it goes in the upper all the way and it closes fine with the new BCG.

OK, what else could keep it back?

I look down into the gas key and could hardly believe it.

So this is a strange one, at least for me, and I relearned the lesson about cleaning BCGs. Always clean out the gas key. I know better, I just wasn't thinking gas key.

What are the odds of this?

 

[RainDodger]

That's the weirdest thing I've ever seen!

I would be playing the lottery anymore because you just blew your 1:1,000,000 chance.

 

[Corpral_Agarn]

Hang on.

Is that a primer in the gas tube?

 

[Walkalong]

Yep. I ran a tiny brush into the gas key last night, and even stepped outside of the shed (into the semi dark yard) to spray some cleaner in it, but wasn't paying close enough attention. I found it after work today when I inspected everything more closely in the light.

So, where was it hiding all this time, and how did it hit the jackpot?

 

[taliv]

well, it's the gas key, not the tube...

the late, great Pat Rogers had a book of stuff like that, including that. I recall him mentioning it in a class once. Pretty rare, but it has happened before.

edit: i would have guessed the odds of it randomly bouncing perfectly into that tube are so small as to be practically impossible. it makes me think when the action is cycling, there is some suction, which i never would have guessed, given the pressure. possibly a venturi effect?

 

[Walkalong]

well, it's the gas key, not the tube...

Silly me, yes, the gas key.

 

[ACP]

wow. what are the chances?? never seen anything like that before. glad you cleared it and are back up and running!

 

[WestKentucky]

Did you have to pull the gas key off the carrier to get it loose or did you manage to free it without further disassembly?

 

[Arizona_Mike]

Interesting!

I've had a 300 BLK case get stuck between the gas key and the charging handle, which required some work. I've also seen AR15 (not mine) so badly jammed up with a squished live .22-250 round that I could not separate the upper and lower.

Never seen that before however.

Mike

 

[Dr.Rob]

That is a one in a million malfunction to be sure.

 

[TJohn]

That is the first one like that, that I have seen. However, I have had a blown primer wind up capping the gas tube, thus not allowing the bolt to go into battery. On another occasion the primer wound up under the trigger bar, so the trigger would not reset. Blown primers do find ways to get into the most inconvenient places.

 

[mstreddy]

Folks, that's actually the second one of this that I've seen. Around 3-4 months ago a guy walked in to the range I frequent and wanted to shoot his AR with some friends.
He goes in to the range, comes out about 5-10 minutes later and asks for some advice as his AR is having some malfunctions. It's basically working as a single shot.
We look at his chamber, check out the bolt, gas rings, all look good. We have him try some different ammo, no joy. I suggested he try either a different upper, or maybe a different BCG.
The range guys lent him the BCG from one of the rentals. And presto, it's shooting just fine. So, now we start looking at his BCG real good. He notices that the gas key seems to have something stuck in it.
Wouldn't you know it, there's a spent primer in there. Apparently the last time he fired it, one got loose, and ended up there. And it was all the way at the back end of it. Walkalong's seems closer to the front. So, it was allowing the gas key to close on the tube, go into battery, fire, but it would interrupt the rest of they cycle.

We don't know if/how he got that out, but at least it answered the malfunction questions.

So, yeah, it's really a one-in-a-million event. And now, I've "witnessed" it happening twice. I think I'm going to buy a lottery ticket.

I've seen other loose primers end up somewhere inside the actions in ARs, Glocks, Uzi's and others. I even saw one once around the charging handle. But those gas key insertions are something else.

Walkalong, how did you get it out?

 

[Walkalong]

I used a hand drill with a bit that just fit in the key. I started it slowly until it grabbed good (Cut through and started pulling the soft brass up into the flutes) and pulled the primer out with the bit.

Mine would go into battery but the BCG was held back just far enough the firing pin wasn't hitting the primer. I had to remove both pins to get it apart.

 

[Howard Roark]

That happened to me twice over a span of a couple of months several years ago when I was shooting an AR .223 match rifle for highpower.

Between pretty warm 80gr 600 yard line loads and occasional loose primer pockets from well used brass I would loose a few primers here and there. A couple of them wound up in the gas key just like yours. One was rolled up and passed enough gas to sluggishly cycle until enough carbon built up to shut it down completely.

I used a thin brass rod to drive them back out of the key after it was removed from the bolt.

The problem was eventually permanently fixed by switching to a bolt gun!

 

[taliv]

a slightly more common and much more annoying malfunction is when the primer gets up there and then falls into the cam pin slot. it prevents the cam pin from either unlocking or locking depending. the harder you pull, the more you crush the primer cup in there and the more stuck it gets, so early diagnosis is key, at which point you can invert the rifle and shake it which allows the primer to fall into the charging handle and then you can retract the bcg.

 

[Nature Boy]

That is wild.

Not sure what the Powerball is up to, but I'd go buy a ticket tonight

 

[Slamfire]

a slightly more common and much more annoying malfunction is when the primer gets up there and then falls into the cam pin slot. it prevents the cam pin from either unlocking or locking depending. the harder you pull, the more you crush the primer cup in there and the more stuck it gets, so early diagnosis is key, at which point you can invert the rifle and shake it which allows the primer to fall into the charging handle and then you can retract the bcg.

I consider this thread and the continuing discussion another good reason to dislike the AR design. I am a fan of the M14/M1a and that action has a lot of open space. I have never blown a primer in a M1a, but if I did, the chances of it falling out of the action and not tying anything up is much better than the enclosed design of the AR.

I have had blown primers fall down into the trigger group of my AR15, I can recall clearing jams for others when blown primers got between the bolt group and the upper. I did have a staple tie up my match AR15. I have no idea how that staple got into the shooting case, but I carry my AR15 to the firing line with an open chamber indicator holding the bolt back. That staple got into the action and I could not get the bolt to close. I could not see the thing either, that staple was stuck on the barrel breech. I ate up 20 minutes of my allotted 30 minutes for my firing relay trying to figure out why I could chamber a round but not close the bolt. I disassembled the rifle twice and only on the second time did I see that staple in the forward part of the barrel extension stuck against the breech of the barrel. I guess I am lucky that staple did not find its way down the gas key. I would never have figured that out in 20 minutes. Junk happens and if it gets inside a design like the AR, and most designs are like the AR now, that junk will rattle around till it jams up the mechanism. I am confident in saying that junk will fall out of the Garand design and you won't even know it.

I do appreciate the advice on how to clear primers rattling around the bolt carrier group, I hope I remember it, and not become too hasty to pull on the charging handle. I still shoot match AR's, they do shoot accurately, thankfully I don't have to rely on one for my life.

 

[M1key]

Popped primer in the cam pin slot. Before I caught it, I had fired several rounds all with subsequent popped/blown primers.

Ammo: Winchester Q3131 (w/crimped primer)

yep

M

 

[Legionnaire]

That's a strange one to be sure! Does make you wonder where that primer was hanging out before deciding to move to the gas key ...

 

[Tirod]

We're blaming the gun . . .

when milspec ammo requires that it be crimped into the pocket. Millions of M16's have been in service for decades, in 22 years I've never heard it reported on the firing line or in use. But take one to a local neighborhood range and use commercial ammo and we have at least 4 instances reported in one thread.

How much of this ammo was reloads with primer pockets reamed to make them easier to insert on the press?

Let's consider all the factors before blaming a system of firearm and ammo that the DOD has working in place over 45 years without the issue. Along with that - most malfunctions are ammo, magazines and the operator. I would definitely put using problematic ammo not meant for service rifle use as an operator issue. That also covers reloads with no crimps - another milspec requirement for government autoloaders. Bullet setback is another issue which commercial and reloaded ammo doesn't adequately address.

I get a similar problem at work at the auto parts store - my high end vehicle is misfiring and runs badly. I always ask what grade gasoline are you using and the face the owner makes is the same. It's the wrong grade gas - the cheapest they can buy - and in MO it's mandatory 10% alcohol, too. For the most part that bargain gas tests at 15% according to most fleet buyers.

The problem is that it's self inflicted.

 

[Walkalong]

I am not blaming the gun, only reported what I found to be a fascinating event.