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Discussion Starter · #1 ·
So I built a .300 Blackout pistol. Lower was a 80% I finished and the upper was assembled and test fired by a major builder. Im. Not going to name anybody until we work things out.
Process leading up to the explosion.

Ammo arrived about 3:30 yesterday afternoon. My new optics came in the mail just before and I had just finished installing them and bore siting.
I loaded 10 rounds into a 20 round pmag and stepped outside to my 50 yd range. My son had already set up paper and I was going to start out at 25 yds.
The ammo was new 175 gr HPBT.

I fired 2 shots, needed to adjust up, fired 1 shot and adjusted until shot 7. Shot 7 exploded when I pulled the trigger. The magazine which I was using as a forward grip at the time exploded, the upper bulged, and the BCG is shredded. If you look at the pictures of the BCG you will see. You can also see the casing shredded inside the chamber.
I fired 6 rounds safely, the holes are in the paper, the 7th round did not hit the paper and the brass is inside the chamber still for it. I have 6 empty casings, and 43 loaded rounds left in the 50 count box. With the casing still inside the weapon all rounds are accounted for. This is the first 300 blackout fired on my range so there is no possibility that I crossed calibers or something like that. The breech was never exposed to anything that could cause a blockage.

I strongly feel that round number 7 was double charged causing the failure. Please check out the pictures and share your opinions. Sorry I did not get the best pictures, I took them immediately after the failure. My hand was a little sore.
 

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TFF Chaplain
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I'm glad you got through that with only a sore hand. It could have been a lot worse. Thankful God brought you through that without worse damage to you.

Keep us posted on what you find out.
 

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If the facts are as stated...either
It WAS a double charge or
The round was'nt crimped and the bullet seated itself from recoil much deeper in case,raising pressure
I'm with zant, it's either the ammo or a bore obstruction, and a plugged bore on an AR platform "usually" results in a barrel bulge.
New ammo?
Who made it?
Hollow base bullets?
What brand?
 

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Guy on the bench next to me was shooting factory rounds when his gun KB'd. It cut his hand and his head. We got him stabilized and sent to the hospital. I haven't yet heard the final result on his case.

I think the bottom line is that I like shooting my home made ammo because I do the QC on it, make sure it's made up right.
 

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Unfortunately it’s all about what you can prove and not what makes the most sense. I don’t want to borrow trouble so let’s see what they have to say, I’d be very interested to hear everyone’s response. Most importantly you and your family are all okay.
 

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Discussion Starter · #14 ·
What did the brass look like after? How did it damage the upper, if the brass was still in the chamber and still intact? Was it a case head separation? Could it have been a out of battery discharge?
The brass looks like an old shotgun wad, it is about 1/4” out of the chamber. I will recover the brass next week after talking to the ammo and upper people.

Guy on the bench next to me was shooting factory rounds when his gun KB'd. It cut his hand and his head. We got him stabilized and sent to the hospital. I haven't yet heard the final result on his case.

I think the bottom line is that I like shooting my home made ammo because I do the QC on it, make sure it's made up right.
Thats normally my attitude as well, this was a new build and a new caliber so I wanted the first rounds to be factory since I couldnt find any brass and Im getting low on primers too.

The ammo was Freedom Munitions and the upper was the “Grimace” assembled and test fired by Team Delta tactical.
 

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Discussion Starter · #15 ·
Guy on the bench next to me was shooting factory rounds when his gun KB'd. It cut his hand and his head. We got him stabilized and sent to the hospital. I haven't yet heard the final result on his case.

I think the bottom line is that I like shooting my home made ammo because I do the QC on it, make sure it's made up right.
I very much feel that I got lucky in this situation. I had a .44 mag blow.up on me about 22 years ago. It dinged my safety glasses hard, blew a couple holes in the lane dividers at the range and left a trail of gouges up my hand and forearm. Ruger took care of that one and there was a recall on the ammo a few months later.
I don’t know how many rounds I have fired over the years but the odds of this happening twice are about the same as hitting the lottery 2x Im sure. Maybe I should buy a ticket.

Thanks for the feedback guys, Ive built quite a few weapons over the years and some my kids use so things like this have me questioning everything.
 

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Discussion Starter · #16 ·
Good grief man! Glad God was looking out for you! Hope you doing ok.
Hows the nerves holding up?
I think I am good to go but haven't shot today.

Was'nt doubting what happened-as Trap said,if the barrel was'nt obstructed-it can only be the ammo...
Who made it?
I did not think you were, just thinking about tearing it down. Thats the hardest part is waiting for that.
 

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Discussion Starter · #18 ·
My question is, can the remaining rounds be weighed to see if the powder charges are different?
Depending on what happens I plan on doing that if they do not make me send the remaining rounds back for them to investigate. I can get a weight on the remaining loaded rounds to look for any major discrepancies.
 

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Depending on what happens I plan on doing that if they do not make me send the remaining rounds back for them to investigate. I can get a weight on the remaining loaded rounds to look for any major discrepancies.
Sorry about what happened and glad you're okay.
I would do just that with the remaining ammo.
 
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