Primer blowout. What should I do?

C-doodle

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I built a garbage grade .300 blk pistol. Today I went to test fire it and in the first 15 rounds I had two primers blow out so I stopped shooting it. (Primers came all the way out of the case)

It is a pistol length .300 with a 7.5" barrel. I was shooting armscor 147gr.

I haven't ever dealt with this before. Not really sure what I should do about it. I was thinking about tossing a complete BCG from a different rifle in it to see if that fixes the issue. Or should I leave the gun alone and try some higher quality ammo first? Or just take off the upper and throw it away?

All of the upper parts are from bear creek arsenal. The QC on assembly was terrible. All of the bolts on the handgaurd and gas block we're finger tight and the gas key had not been staked. I completely disassembled the whole thing and put it back together with things like tools and locktite before I even tried it.

I would like to be able to run the wolf .300 thru this thing when it hits the shelves but these blown out primers made me a little nervous.

Thanks.
 
Not reloads but it was cheap ammo. Armscor 147gr.

Part of the reason I gave them a try was because they are less then an hour from my house. I can drive it back to them lol.
 
more than likely the ammo
 
Was the spent round stuck or hard to extract?

Typically blowing primers is a pressure issue.

I’d email them (or call them) with lot numbers and ask for a refund. A quick google search showed this is a common problem with their 300BLK ammo. I’d stop shooting it altogether
 
The spent round would actually eject. The only way I even noticed was that it would fail to cycle because there was a loose primer keeping the bolt from going all the way forward again. It may have happened more then twice but those were the two I noticed.

So do you think it's safe to get some more reputable ammo and try running it again?

I only bought two 20 round boxes I'm not too worried about a refund. I might call the pawn shop I bought it from and let them know though.
 
On three occasions within 4 yrs I've seen blown primers on 5.56 military M4s. I happened to be on the range when primer lodged itself under the trigger, tying up the gun/dead trigger. Takes a few minutes to clear when it happens. First was with M855 and last two M855A1 ammo. A1 is higher pressure and both rounds have crimped in primers.

CD
 
Pull your upper, firing pin & extractor. See how many pieces of Scotch tape you can put on the base of a round and the bolt will turn/close. A cheap chamber clearance test. When I’ve checked, the tape’s ~ 0.003”. You’ll be able to see that ammo & chamber comparison.
 
Sounds like a pressure issue with the ammunition. One year I got in 60 K rounds of 5.56 from Winchester. Was having the same issue in different rifles. Out of a box 20, 2 or 3 would blow the primers, crimped primers I might add. Identified the lot number called Winchester and they requested a case for testing. Received a letter back that they concluded their testing and would be replacing all of the ammo in that lot. I think you will be fine to get another brand of ammunition and try it. I’d load one round at a time for about 5 rounds and inspect to casing for pressure issues just to be safe. After that if there are no signs of pressure issues, load up and shoot away.


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Check the length at the shoulder of new and fired brass. If you don’t have shoulder measuring tools, I could check it for you, I’m nearby.
 
Check the length at the shoulder of new and fired brass. If you don’t have shoulder measuring tools, I could check it for you, I’m nearby.
I have some calipers but I don't k ow if they would work for that kind of measurement. If you want to help me measure it that would be great. I'm going to be out of town until Monday though.

I am north of Pittsboro near bynum. I don't mind driving a little ways.
 
I have some calipers but I don't k ow if they would work for that kind of measurement. If you want to help me measure it that would be great. I'm going to be out of town until Monday though.

I am north of Pittsboro near bynum. I don't mind driving a little ways.
I’ve use these:
https://www.brownells.com/reloading...spx?avs|Manufacturer_1=SINCLAIR+INTERNATIONAL
https://www.brownells.com/reloading...spx?avs|Manufacturer_1=SINCLAIR+INTERNATIONAL
https://www.brownells.com/reloading...spx?avs|Manufacturer_1=SINCLAIR+INTERNATIONAL
 
The primmer might not be crimped in place.

John has a valid point. Not all manufacturers crimp the primers. Couple that with quality control issues and it would be easy for a primer to pop out of an out of spec primer pocket.
 
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