Costa Mesa AR180 malfunction

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[ARCHIVED THREAD] - Costa Mesa AR180 malfunction

Posted: 1/6/2019 9:28:44 PM EDT

After about 70 rounds downrange today with no issues, then this happened....

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.

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Fortunately, my son was wearing eye protection and not directly holding the mag while shooting.
Other than a sore hand and a small abrasion on his cheek, no injuries.

The gun, of course, was done for the day.

Obviously, the Bolt Carrier is toast. The Bolt is probably damaged also. I haven't managed to get it apart yet.

Posted: 1/6/2019 9:33:29 PM EDT

[#1]

Oh no!

Posted: 1/6/2019 9:40:08 PM EDT

[#2]

Ouch! That hurts.

Glad everyone is safe and sound though.

Any theories as to the cause? Overcharge maybe? Never seen that big of a chunk blown out of a bolt before.

Posted: 1/6/2019 9:45:04 PM EDT

[#3]

Looks like an out of battery detonation. I have seen that happen on an AR-15. It blew out the mag and ruined the ejector, but no other damage...Bill

Posted: 1/6/2019 10:04:47 PM EDT

[#4]

Oh wow. Just glad nobody was injured.

Posted: 1/6/2019 10:04:51 PM EDT

[#5]

Here's some of the debris along with a round that might have been in the magazine.

Those pieces were in the upper receiver. The bullet wasn't in the barrel and wasn't found.

Attached File

Posted: 1/6/2019 10:31:05 PM EDT

[#6]

Mist importantly, I'm glad your son is OK. Was the ammo factory ammo, or reloads? I have seen three weapons blow up, and all of them were with reloads.

Posted: 1/7/2019 12:15:13 AM EDT

[#7]

Ugh...another AR-180 set sail for Valhalla!

Posted: 1/7/2019 12:40:39 AM EDT

[#8]

Glad he is safe. Sorry that that happened! Looks like it was out of battery?

Posted: 1/7/2019 8:45:06 AM EDT

[#9]

If it was out of battery the firing pin wouldn't even be able to hit the primer... right? It's an inertial firing pin held back with a spring, shouldn't be able to touch the primer until it's fully locked, I thought.

Posted: 1/7/2019 9:33:53 AM EDT

[#10]

Wow!

Like everyone else, I’m curious about ammo type.

I’m glad the shooter was okay.

Posted: 1/7/2019 12:18:53 PM EDT

[#11]

Damn, are there any bulges to the upper and lower receivers?

I have seen on GB that an AR180 BCG listed but not sure if it is still on there. Then again, it could have been a listing for a B series BCG.

I would try see if Rick on AR180S.com has extras or a lead for an original.

Posted: 1/7/2019 1:21:33 PM EDT

[#12]

I suspect the cam pin jumped out of its guide and allowed the bolt to turn. That has been known to happen and will allow it to fire out of battery.

You would need to check it out very well even with a new parts to make sure it won’t happen again.

Good thing is most problems with the receiver, other than a trunion, that get messed up can be fixed. Big hammer and a tig welder can put her back in service. Although it may not look pretty when you are done.

Contact me through my site and we can figure out whatcha need to it fixed.

Posted: 1/7/2019 1:29:24 PM EDT

[#13]

I would also like to see pics of the trunion locking lugs. Might give us some clues.

Posted: 1/8/2019 12:07:49 AM EDT

[#14]

Quote History

Quoted:
Wow!

Like everyone else, I’m curious about ammo type.

I’m glad the shooter was okay.

View Quote

I'll post some more pictures soon. I did get the Bolt out of the Carrier.

As for the Ammo used, I learned a few years ago that it's foolish to save a few cents with cheap reload ammo.

I had a Colt 1911 that I was shooting cheap gun show ammo through at the range one day and the Range Officer commented on how much smoke it was making. The very next round wouldn't chamber. So I put the gun back in my bag and gave him my remaining rounds. He said his Glock would eat anything. I hope it did.

When I got home, I pulled the gun apart and found the last bullet still in the barrel. The reason the next round wouldn't chamber was because that bullet had only travelled a short distance and was blocking the end of the chamber.
If it had travelled just a little bit further, I could only imagine how that gun would have fragmented in my hands if the next round went off normally. Thankfully, that was left to my imagination only.

So anyway, all my ammunition is first load stuff since then.

Posted: 1/8/2019 1:25:05 AM EDT

[#15]

I couldn't find any damage to the Lower.

This is the only damage I could see on the Upper:

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Nothing that I can see here:

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Posted: 1/8/2019 1:30:29 AM EDT

[#16]

The Bolt Carrier fragment deposited itself inside the lower.

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Bolt and Cam Pin. The Cam Pin was damaged, but I think the Bolt looks good.

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Posted: 1/8/2019 10:03:18 AM EDT

[#17]

Frontier ammo has been linked to a few kabooms lately. I thought I’d mention that just in case.

Posted: 1/8/2019 1:56:36 PM EDT

[#18]

When you get some new parts I think you will see that the cam pin has very little engagement with the guide. A custom pin that is longer should fix you right up.

I can clearly see where it jumped out of the guide. It wasn't locked when it dropped the hammer.

The fact that early Costa Mesa guns used an AR-18 firing pin could have contributed to this malfunction. If the hammer dropped and the bolt carrier was not all the way forward but the bolt was all the way back, it can still contact the tail of the firing pin. I don't think it could do that with a later 180 firing pin.

I'd be happy to help you get this fixed and would love to pics of your gun on my site.

Posted: 1/8/2019 2:36:23 PM EDT

[#19]

Quote History

Quoted:
When you get some new parts I think you will see that the cam pin has very little engagement with the guide. A custom pin that is longer should fix you right up.

I can clearly see where it jumped out of the guide. It wasn't locked when it dropped the hammer.

The fact that early Costa Mesa guns used an AR-18 firing pin could have contributed to this malfunction. If the hammer dropped and the bolt carrier was not all the way forward but the bolt was all the way back, it can still contact the tail of the firing pin. I don't think it could do that with a later 180 firing pin.

I'd be happy to help you get this fixed and would love to pics of your gun on my site.

View Quote

@BigRix do you have a photo of an AR18 firing pin alongside an AR180 firing pin? If one (or more) of my AR180's have AR18 firing pins, can I/should I, swap them out for AR180 firing pins?

Posted: 1/8/2019 6:22:55 PM EDT

[#20]

Closest thing I could find was this comparison of the 18, Early Howa, and standard production 180 pins.

I would not replace the 18 style pin but rather double check how much engagement your cam pin has.

Posted: 1/8/2019 11:52:41 PM EDT

[#21]

Ar-180 firing pin in the rear, Ar-18 in front

-Josh

Posted: 1/9/2019 12:13:50 AM EDT

[#22]

I don't know why so many people jump to OOB firing when it's usually case head separation.

Some brass just has imperfections in it and doesn't get caught.

What type of ammo was it?

I see Winchester head stamps but maybe I missed the details of the ammo.

Posted: 1/9/2019 12:17:26 AM EDT

[#23]

case head separations occur when fully in battery, not out of battery.

Posted: 1/9/2019 10:32:00 PM EDT

[#24]

Quote History

Quoted:
I don't know why so many people jump to OOB firing when it's usually case head separation.
.

View Quote

If a case head separated, how would the powder ignite?

Posted: 1/9/2019 10:55:50 PM EDT

[#25]

Quote History

Quoted:

If a case head separated, how would the powder ignite?

View Quote

The case head seperates AFTER the powder ignites. Original WWII MP44 kurz ammo has a bad tendancy of doing that (I've had it happen three times).

Posted: 1/10/2019 2:54:47 AM EDT

[#26]

Quoted:
Ar-180 firing pin in the rear, Ar-18 in front

https://i.imgur.com/47gAnch.jpg

-Josh

View Quote

and this is the Firing Pin that was in the gun when it malfunctioned.

I hadn't noticed that divot on that shoulder until looking at this photo.

Posted: 1/10/2019 12:37:15 PM EDT

[#27]

that divot on the shoulder most likely happened during the out of battery detonation when the firing pin was blown bac violently.

Posted: 1/10/2019 12:52:06 PM EDT

[#28]

This thread has inspired me to inspect my Sterling AR-180.... appreciate all the details everyone is providing

Posted: 1/13/2019 5:52:13 AM EDT

[#29]

I'm glad that no one got hurt in this incident with the KABOOM. Thanks OP for posting and sharing all the photos and the experience. I have two AR-180 (Costa Mesa and Sterling) and I would hate if that would happen with any of them. All the best.

Posted: 1/13/2019 11:48:14 AM EDT

[#30]

Quote History

Quoted:
I'm glad that no one got hurt in this incident with the KABOOM. Thanks OP for posting and sharing all the photos and the experience. I have two AR-180 (Costa Mesa and Sterling) and I would hate if that would happen with any of them. All the best.

View Quote

Thanks Mauiblue (and everyone else!).

The damage seems to be isolated to just a few parts. So I'm hoping to find replacements and be back in business. Any help along those lines would be greatly appreciated.

Posted: 1/13/2019 4:12:54 PM EDT

[#31]

Quote History

Quoted:
This thread has inspired me to inspect my Sterling AR-180.... appreciate all the details everyone is providing

View Quote

I shall do the same.

Posted: 1/13/2019 7:55:05 PM EDT

[#32]

I've been seeing parts for AR-180 on Gunbroker. Check them out. I was fortunate to have a small cache of main parts for my AR-180 rifles that I was given from the previous owner. Also Bigrix might be able to help you get the parts you need to get the gun running again. Good luck and be safe.

Posted: 1/23/2019 1:19:46 PM EDT

[#33]

If I were to guess, it looks to me like the bolt carrier broke first. That would allow the bolt to fully close but not lock. I think it would act like an out of battery by firing on an unlocked bolt.

[ARCHIVED THREAD] - Costa Mesa AR180 malfunction

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