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Discussion Starter #1 (Edited)
Don't know what caused it, yet. Pics below.

Anyone else have this happen?
 

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I haven't had one explode, but I did have a small piece of the bolt break off. It was a German, factory bolt, carrier, etc. I was surprised and you are the only other person I've read about having problems with one.

Small world.
:)
 

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Discussion Starter #3
For the record it was an FMP bolt head.
 

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Looking forward to seeing the pictures, where did it "explode"? Did it break near the rollers? the bolt face? Curious.
 

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Discussion Starter #5
Looking forward to seeing the pictures, where did it "explode"? Did it break near the rollers? the bolt face? Curious.
Pretty much from the bolt face to the roller on the extractor side.
 

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I had a MP5 do that right after I bought it. It seems the prior ownet had replaced the barrel incorrectly and the bolt gap was way off. Broke a German bolt head AND carrier. Look at the round part of the carrier. It took a while but I found a crack in mine. I had RDTS replace entire bolt assemble, check the gap, and it's been wonderful since. I got pay $1200.00 to learn to check the bolt gap on any "pre owned" HKs I buy.
 

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Tear-out failure--almost looks like the roller on the extractor side refused to slide IN and when the bolt head moved back, it (the roller) tore it's way forward and took a significant portion of the bolt with it. Following the paths of least metal to fail--you can see how thin some portions of the cross section actually are. The last little bit of failure was that which leads directly to the firing pin hole--smoother on the top (closer to the ejector) and more jagged on the bottom (where the metal is thicker). Check your trunion to see if the roller did any damage as it and the bolt were forced back and destroyed.

Sorry about your weapon.
 

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Aww, c'mon. Rub some Tussin on it and get back to the range. ;)

Seriously, YOWCH!! Hope you and the rest of the gun are okay. Any peen marks on the bolt face or breech face?
 

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Ouch. My MP5 wasn't that bad. Is the other roller still in the other side of the bolt head? Is the roller one from this side still intact? What does the inside of the trunion look like? I wonder if the extractor didn't some out first and end up in between the roller and the trunion. Very strange and very scary. I'm glad you are ok. I will forward this thread to Ralph at RDTS. Please keep us posted as to the cause.
 

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Discussion Starter #15
Tear-out failure--almost looks like the roller on the extractor side refused to slide IN and when the bolt head moved back, it (the roller) tore it's way forward and took a significant portion of the bolt with it. Following the paths of least metal to fail--you can see how thin some portions of the cross section actually are. The last little bit of failure was that which leads directly to the firing pin hole--smoother on the top (closer to the ejector) and more jagged on the bottom (where the metal is thicker). Check your trunion to see if the roller did any damage as it and the bolt were forced back and destroyed.

Sorry about your weapon.
Looks as if the only thing damaged was the bolt head.
 

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Discussion Starter #17
Ouch. My MP5 wasn't that bad. Is the other roller still in the other side of the bolt head? Is the roller one from this side still intact? What does the inside of the trunion look like? I wonder if the extractor didn't some out first and end up in between the roller and the trunion. Very strange and very scary. I'm glad you are ok. I will forward this thread to Ralph at RDTS. Please keep us posted as to the cause.
The other roller is still there along with the roller plate and pin. I couldn't find the other roller do to it getting dark, and haven't been out there since. Trunnion looks to be fine.

The only thing I can find is that the spent case was stuck partially out, but not ruptured, and the timing on my gun isn't off, maybe just a crack that finally gave?
 
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