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Ammo Go Boom (the bad way)


bbkchicago

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So I'm out on the range today with the missus, decided we'd stick to rimfire and cook off some old bricks since I have new ones and I like to do "stock rotation" and shoot my oldest ammo first. I load a couple of mags from my bucket o' ammo, then decide to break into a fresh brick of American Precision 22lr 40 gr copper plated LRN ammo. 1190 claimed FPS, "superfast" Mexican made ammo I purchased for $55 / 500 round brick at a gun show back in GA in 2013.

 

Sorry for the long background, just want to cover all bases. Anyway.

 

I'm shooting out of my KelTec CP33 and now that it's broken in this pistol eats whatever ammo you throw at it and is crazy accurate and reliable. Then theres a weird "snap" on one round. Smoke is coming out the side of my gun.

 

I drop the mag, check the round and it's loaded the next round in the chamber, I pull that out and check my barrel for a squib or anything. Seems perfectly fine. I resume shooting. I'm hammering nails, zinging a 4" bullseye from 50' taking a shot about every 1 or 2 seconds. Then another snap and I feel burning powder hit my face. Smoke coming out the side of my gun again.

 

I repeat the same checks, pull the mag and the live round from the chamber. Everything seems fine. I can't find the last shell casing I shot because there are so many on the ground. I spend about 5 minutes inspecting everything and all seems well... but I don't have a good feeling.

 

I decide screw it, I'll finish this mag off. I chamber a round and fire. BAM. Feels like someone hit my hand with a hammer, gun flew right out of my hand and my safety glasses got flung off my head. I had black soot all over my hands and face, and my safety goggles got hit by something very hard and were messed up.

 

I unload the gun and say screw this. I find that EVERY shell casing from the American Precision ammo has a bulge directly opposite where the firing pin hits the rim. Three of the shell casings have blown out right where the rim meets the body. Only one American Precision casing wasn't bulged. The other Federal ammo I was shooting has zero bulges or anything wrong.

 

The inside of my gun is filled with little pieces of metal, I think lead and not brass. The lower lip of my barrel might be slightly out of round but it might be like that from the factory as a sort of chamber feed ramp? I don't know.

 

I've had this happen like once before, had little issues and a squib once...but I've never seen an entire box of ammo that acts like this. Again, the other ammo has NO bulging or deformities or any issues.

 

Anyone have any thoughts here? I'm out of my territory I think. I saved all the shell casings I could find and haven't cleaned the gun yet. I tried to reach out to American Precision but their phone is disconnected, their website says "contact us if you want to buy our loading machine" and they have garbage reviews.

 

I know CCI takes this sort of thing seriously and does like actual testing and metallurgy to determine the issue

...which surprisingly is NEVER their ammo ;)

 

I freaking LOVE this gun and I hate that my shooting day was cut short...but I'm glad I have my eyes and hands intact. I never thought a 22lr could hurt like that, but for real my right palm is bruised where I was holding the gun. This was like a contained grenade or something. What gives??

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Slamfire, with the rounds firing before the round is fully in the chamber, that's why the brass is bulging. Maybe it's not a noticeable problem with other brands because, somehow, the primers on these are more sensitive.

 

Make sure the firing pin moves freely (like no Froglube gumming up the spring; not accusing, but I've seen it); make sure the chamber and ramp are clean; check the "headspace."

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Anyone know an easy way to post pics and video here? Should I just put a video on YT and share that way?

Posting a video elsewhere and linking to it is the only way for videos. Pictures can be uploaded directly as attachments if you click "More Reply Options" below right.

 

Even if you're waiting 1-2 seconds between shots, I'm still not sure your rounds are going into battery all the way, and once every few magazines you get slamfire. The rounds that are "disappearing" are going somewhere. They don't evaporate. They're getting ejected after detonating, even without pulling the trigger.

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Anyone know an easy way to post pics and video here? Should I just put a video on YT and share that way?

Posting a video elsewhere and linking to it is the only way for videos. Pictures can be uploaded directly as attachments if you click "More Reply Options" below right.Even if you're waiting 1-2 seconds between shots, I'm still not sure your rounds are going into battery all the way, and once every few magazines you get slamfire. The rounds that are "disappearing" are going somewhere. They don't evaporate. They're getting ejected after detonating, even without pulling the trigger.

Sorry, I was not being clear. I am sure all rounds were accounted for and that there was no slam fire. I was saying that I couldn't find all of my shell casings because of the grass and stuff.

 

Its possible that not all rounds were completely in battery, but on this last round I am 100% sure it was because I was definitely skeptical after the red flags. I specifically loaded the round, checked that the bolt was firmly seated and everything was fine. I wasn't checking between every shot so maybe OOB was possible with some of the others, but this blew up like crazy even when the bolt was all the way closed.

 

Humor me for a minute - is it possible that after ignition, as the shell casing is pushing the bolt rearward that theres still enough pressure for a case blowout like that? Again, zero squibs and I was diligent about checking when she started acting weird.

 

Did you watch the video? I want to compare my bbl with other CP33 and see if they're all beveled like that.

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Well, sorry if I misunderstood about some of the shells. The brass still has to get bulged when it's not in battery. If you're absolutely certain they all went into battery all the way, then they're getting bulged as they're being extracted, with some of the propellant expelling out the ejection port while it's still burning. So the rounds are loaded to exceedingly high pressure, or the crimp is so tight that the base of the shell is blown out (in some cases) just as the bullet is released, or the brass is so weak that the base ruptures before the bullet is released from the crimp.

 

It would be interesting if you had found an ejected round with the base blown out and the bullet still in the crimp, but I'm disinclined to believe that the brass is weaker than the crimp, especially because you didn't end up with any bullets stuck in the barrel. My next guess is that they're loaded too hot. It might be interesting to try them in a bolt rifle or a revolver, maybe with a chronograph.

 

It's clearly not safe to continue using them with a semi-auto, at least that one semi-auto.

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I had a 10mm case rupture in my g29 and it really got my attention.the blast blew my hand off the gun and the mag a few lanes down.luckily,besides some hand bruising I was ok.I was shooting 200gr aluminum cased blazer.had to pound the slide open to retrieve shredded casing.sent the gun to glock and most parts were replaced other than the frame for no charge.sent remaining ammo back (500 rds) to cci and was given a full refund.I know there are many that have no problems with aluminum cased ammo,but I only shoot brass now.
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Can you pull the bullets and weigh the powder in a few rounds? Dont know how to check the amount of primer, but it looks like the primer could also have considerable power, based on whats in that reloading video. Maybe fire just the primed case and check decibels/volume.

Good idea. How many do you think I should try this on? Also what is a good comparison round to use? I have probably 20 different brands and maybe 50 different types of 22lr to compare with. Maybe just CCI standard? Should I compare with something the same age? (~6 years old). Does anyone know of calipers that can measure case thickness down by the rim? I've got some pretty crazy stuff in my lab, but nothing that can reach down a 22lr casing and accurately measure wall thickness. I may be out of my league here.

 

 

PS: I heard back from the manufacturer, and they're being cool. Apparently this was an older batch of CCI that sort of came out and then instantly disappeared from the shelves. They're doing some investigating and I'm going to wait and see what they think.

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Well, sorry if I misunderstood about some of the shells. The brass still has to get bulged when it's not in battery. If you're absolutely certain they all went into battery all the way, then they're getting bulged as they're being extracted, with some of the propellant expelling out the ejection port while it's still burning. So the rounds are loaded to exceedingly high pressure, or the crimp is so tight that the base of the shell is blown out (in some cases) just as the bullet is released, or the brass is so weak that the base ruptures before the bullet is released from the crimp.It would be interesting if you had found an ejected round with the base blown out and the bullet still in the crimp, but I'm disinclined to believe that the brass is weaker than the crimp, especially because you didn't end up with any bullets stuck in the barrel. My next guess is that they're loaded too hot. It might be interesting to try them in a bolt rifle or a revolver, maybe with a chronograph.It's clearly not safe to continue using them with a semi-auto, at least that one semi-auto.

I agree, but I don't want to throw any companies under the bus if it's not their fault. I really am not concerned about a $55 brick I bought half a decade ago, but I do want to investigate further to see what the actual problem is and make sure this doesn't happen to anyone else.

 

Did you see the reply below yours about pulling the lead and weighing the powder? What do you think?

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... then decide to break into a fresh brick of American Precision 22lr 40 gr copper plated LRN ammo. 1190 claimed FPS, "superfast" Mexican made ammo I purchased for $55 / 500 round brick at a gun show back in GA in 2013.

...

I agree, but I don't want to throw any companies under the bus if it's not their fault. I really am not concerned about a $55 brick I bought half a decade ago, but I do want to investigate further to see what the actual problem is and make sure this doesn't happen to anyone else.

 

Did you see the reply below yours about pulling the lead and weighing the powder? What do you think?

Maybe you'll learn something by dumping the rounds, maybe not. It can't hurt. 1190 ft/s isn't all that fast, but it sounds like they intended to load them hot.

 

FWIW

Corporation Wiki

American Precision Ammunition, LLC filed as a Domestic Limited Liability Company (LLC) in the State of Texas on Wednesday, February 10, 2016 and is approximately four years old, according to public records filed with Texas Secretary of State.

Maybe it was a Mexican company before then.

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The company has never produced 22lr. This is stuff made by CCI in Mexico that was branded and boxed with their info. I don't know what ever ended up happening with their 22lr product, because it seems like people were pretty stoked about it at first, then it just disappeared from shelves almost overnight.

 

The guy at P.A. said he's traveling but would get with me Wednesday to figure out how I should move forward. I made it clear that I'm not looking for anything and my one and only intention here is to make sure some kid doesn't get hurt.

 

Aside from the couple of splits, it seems like the case bulge is happening right where the bevel in the chamber is - sort of an ad hoc feed ramp. I'm wondering if a weak case combined with that beveled chamber "feed ramp" is causing those bulges, perhaps combined with something else like a hot load. (snicker).

 

I'm dumping the powder after I get off work today. I'll report back what I find and what the company says. If it turns out it's truly not their fault I'm thinking maybe I should delete this thread so I don't throw an innocent legit business under the bus? The US needs more companies like this, and small businesses especially.

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Can you pull the bullets and weigh the powder in a few rounds? Dont know how to check the amount of primer, but it looks like the primer could also have considerable power, based on whats in that reloading video. Maybe fire just the primed case and check decibels/volume.

Good idea. How many do you think I should try this on? Also what is a good comparison round to use? I have probably 20 different brands and maybe 50 different types of 22lr to compare with. Maybe just CCI standard? Should I compare with something the same age? (~6 years old). Does anyone know of calipers that can measure case thickness down by the rim? I've got some pretty crazy stuff in my lab, but nothing that can reach down a 22lr casing and accurately measure wall thickness. I may be out of my league here.

 

 

PS: I heard back from the manufacturer, and they're being cool. Apparently this was an older batch of CCI that sort of came out and then instantly disappeared from the shelves. They're doing some investigating and I'm going to wait and see what they think.

 

 

Not sure, I see bullet pullers listed for .22 but don't know if they'll work on .22 LR. Myself, I'd try a finger-held pipe cutter but not sure if it'll close down on a .22 cartridge - somewhat destructive and MacGyverish.

 

Since all these rounds have the problem, maybe just do one, unless you want to see the variation if any between rounds. Maybe try to find the powder from CCI since your in contact with them, maybe they'll confirm how much powder should be in there Hopefully the rep will tell you any problems that they're aware of and you and confirm them.

 

You barrel face doesn't look right to me, don't see how you can get a good seal on the rim, and if there's any unsupported portions of the case.

 

I'd keep the thread either way, if there's now problem with the round - just acknowledge it. This is a good problem to be aware of, even better when you find the solution.

Maybe do a full root cause analysis on the problem.

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I had a 10mm case rupture in my g29 and it really got my attention.the blast blew my hand off the gun and the mag a few lanes down.luckily,besides some hand bruising I was ok.I was shooting 200gr aluminum cased blazer.had to pound the slide open to retrieve shredded casing.sent the gun to glock and most parts were replaced other than the frame for no charge.sent remaining ammo back (500 rds) to cci and was given a full refund.I know there are many that have no problems with aluminum cased ammo,but I only shoot brass now.
Had similar issue with 9mm aluminum case federal ammo. Haven't shot any since and haven't had one malfunction since. Sent from my SM-G950U using Tapatalk
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So I carefully tapped and pulled apart the following cartridges:

 

American Precision 22lr rn ~2014 (ammo in question)

CCI Mini Mag 22lr HP ~2019

CCI Subsonic hp ~2013

Aguilla Super Extra HP ~2012

Aguilla Super Subsonic lrn ~2011

Aguilla Super Colibri ~2013

 

It may seem like a weird mix of ammo to compare with, but this ammo was stored for roughly the same amount of time and in the same exact location and with the same climate control.

 

For extraction I 3D printed jigs for the cartridges and for the tools

I then tapped the projectiles and measured force required to extract the projectile

All were roughly the same force required, with the Super Colibri requiring less force to extract.

 

Since Colibri is prime only, I didn't use it as a comparison in terms of powder weight. I created an Excel document with the exact weight and rough size of all powder loads, and most were very close. One odd thing I noticed is that the more powerful rounds actually have less powder in them. This is counter intuitive, but perhaps they're using a different powder type which would explain it.

 

My digital microscopes are not too impressive, so I don't have much to share in the way of good microscopy video. My Russian phase phrase contrasted microscope from the 90s was amazing as always though, and I noticed a HUGE difference in the particulate size for the American Precision powder versus all the others. The American Precision powder particulate size was HUGE compared to all other powders granule size.

 

What does any of this mean? Honestly I'm not smart enough to figure that out. And unfortunately I'm sort of at the end of my "knowledge rope" here unless someone can tell me what to check next, or how the heck to measure wall thickness down inside a 22lr casing at the bottom by the rim

 

 

I'll agree on the statement above about my bbl/chamber being weird. No other rounds had this issue, but perhaps this is a bad mix having these rounds with this gun? I did compare with other CP33 and they all have a beveled chamber entrance like this

 

 

Definitely hoping to hear more thoughts here. Still waiting to her back from A.P. today.

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As another potential data point, I have a Ruger SP101 revolver in 22lr that I could use to fire off a few of the suspect rounds if you are interested in the results.

 

I’m in the Naperville, Bolingbrook, Plainfield area.

 

-Keith.

Yes, I'm interested. Do you ever get out to the ISRA range? I'm there every weekend. I shoot at Gat, Maxon, Shore and a few others during the week. (I shoot a LOT).

 

As an aside, I tested in a brand new 10/22 yesterday. Calling these rounds "hot" is an understatement. Noticable increase in recoil, less smoke and about 1350fps. The empty casing ejected about 3x as far as all the other shell casings I shot. The back of the shell was slightly deformed, sort of hemispherical after shooting - but the cases didn't burst.

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a slower or longer burning powder? Its able to push the case out of battery while still burning enough with the bullet in the barrel and cause a blowout? Just a guess.

Can you take the barrel out and see what a cartridge looks like while dropped in the barrel, do the AP rounds drop in freely?

I'll try that today, first I have to meet a forum member to complete a purchase.

 

Also I haven't heard back from AP. I emailed again last night to remind him, hopefully he responds this week and tells me what to do.

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A decade is not old ammo if kept in cool dry place.

It is impossible to give much help over the internet but that will not stop me

My bet is on a dirty chamber. American chambers are traditionally looser than European 22rf chambers. Aquilla is made on old Eley manual product machines. American ammo will not chamber in a quality European 22lr

Using good clean burning ammo I clean every 250 rounds. 100 brush strokes with extra time spent on the chamber.

I will not use Remington ammo. Too dirty.

I suspect a dirty chamber letting some rounds close the breech while others not so much.

Blow back actions do not lock up.

A second thought would be a weak or dirty recoil spring.

Curious to see what you discovered.

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I spoke to a few folks at M CARBO and they confirmed that the "feed ramp" my barrel has is NOT standard. That's crazy, because this was a brand new gun that's only a couple of months old with less than 250 rounds through it. In the video I posted you can clearly see what looks like factory beveling on the bottom half of the breech of the barrel.

 

Perhaps the ammo is hot, too - but in this case I think it's a combination of the ammo and gun. I believe the first explosion blew up in the gun and messed up the chamber. After that, the missing metal from there caused these other failures on these hot rounds.

 

We'll see what KelTec says next. A.P. is fine with me sharing this with them.

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I'll tell you one thing I'm learning quickly - no company wants anything to do with you if they think their product might be at fault.

 

I can barely get a "how are you?", much less an answer to the most basic questions like "is this yours?" or "is this within spec?"

 

Frustrated.

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Sounds like you had an out of battery detonation, or more than one.

 

There are many things that can cause that, but with a rimfire it can be two things, but first what is an out of battery detonation:

 

The round doesn't fully chamber, and the round is set off by the firing pin.

 

What can cause that?

 

Something obstructing the chamber. With rimfires, you can heave leading that needs to be cleaned out, and with enough leading it could hold the cartridge just far enough out to cause what you experienced.

 

A round that's way too long, jams into the lands of the barrel, but is crimped so tightly that it doesn't seat the bullet by force, causing the cartridge to fire out of battery.

 

The last two are a squib, and a piece of broken brass in the chamber.

 

You looked at the cases and what it sounds like you explained was that the wall of the brass next to the rim blew out. That's 100% out of battery detonation.

 

The one thing that throws me for a loop is how your brass looks "Glock'd". It has that unsupported chamber look to it. But in a well designed gun, the unsupported chamber thing really shouldn't matter.

 

I'd look at these things if you can:

 

1. Check for leading in the chamber right before the rifling in the barrel.

 

2. Check the inside of the chamber as best you can just for anything that doesn't look normal.

 

3. Measure the rounds and compare them with what they should be. Are they too long? I'm not familiar with what cartridges headspace off of with that specific gun. I'd assume they should headspace off the rim of the case similarly to centerfire cartridges, but then again I'm not an expert in rimfire aside from owning a couple rimfire rifles and pistols.

 

I'll post a pic of what the inside of my Ruger Mark IV chamber looks like. You'll see it's almost impossible for it to "Glock" brass in the way your gun did which is why I think it may be touching off rounds without the cartridge being fully in battery.

 

cd9ed2ddf62a70db443762e42aa8d23b.jpg

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