7.62 AR-10 mild Kaboom

[Disciple]

I don't think the cam pin was mentioned. Was it found and in good condition? If it sheared off the carrier could be fully forward without the bolt being properly rotated to the locked position.

[georgeib]

I don't think the cam pin was mentioned. Was it found and in good condition? If it sheared off the carrier could be fully forward without the bolt being properly rotated to the locked position.

Good thought. But the OP said the kaboom didn't happen until he pressed the trigger.

[Disciple]

Wouldn't a sheared cam pin allow that to happen? The carrier and firing pin would appear "in chamber" from the rear, allowing the hammer to fall, strike the pin, and ignite the primer, but the bolt would not be properly rotated to lock?

[georgeib]

Wouldn't a sheared cam pin allow that to happen? The carrier and firing pin would appear "in chamber" from the rear, allowing the hammer to fall, strike the pin, and ignite the primer, but the bolt would not be properly rotated to lock?

Oh, I see what you're saying now. Was late when I read your last post. Yeah, that makes sense.

[markm]

I don't think the cam pin was mentioned. Was it found and in good condition? If it sheared off the carrier could be fully forward without the bolt being properly rotated to the locked position.

Interesting. We were unable to get the bolt group from the upper. I got it just about into battery so that we could pull the upper and lower apart. There was a nasty gash in the upper just behind the relief cut (in the upper) for the cam pin to rotate.

A "blow back" burst would align with all the existing clues for sure. Hmmm..

[Pappabear]

Yes, they did confirm that cam pin was trashed. And as an FYI, this MWS had a 20 inch SS barrel with Rifle length gas system.

PB

[sinister]

WOW. Color me perplexed!

[markm]

I'm very much leaning towards the gun firing without the bolt locked. It would explain the damage, and where there was no damage.. extractor etc.

[georgeib]

Yes, they did confirm that cam pin was trashed. And as an FYI, this MWS had a 20 inch SS barrel with Rifle length gas system.

PB

I'm very much leaning towards the gun firing without the bolt locked. It would explain the damage, and where there was no damage.. extractor etc.

What do you guys think the round count on that upper was?

[markm]

What do you guys think the round count on that upper was?

We shoot the MWS guns a lot. But Pappabear would have a better estimate.