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Posted: 7/5/2006 4:55:11 PM EDT
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My M4 carbine jammed in full auto. It fired two of 30 round mag, third no bang. Bolt looked like it had fully chambered, but would not extract. Bounced butstock on tailgate of truck maintaining downward pressure on bolt handle and round came out. Round - Olympic 55 rn, 300 left out of 3k, no other problems seem to be cheap blasting ammo. Primer was hit and pushed halfway out, the case head was darkened/discolored about .20 of an inch down from rim. Cartridge measurments. The OAL - 2.250 normal was 2.247 Base - .372 normal was .370 shoulder - .356 normal was .353 neck - .251 normal was .251 My first thought was that the primer blew, but the powder did not ignite, pushing out the primer and expanding the case slightly. The bullet has not really moved. Would the unburnt powder cushion the primer blast this way. I have checked the measurements with a digital caliper but have not pulled the bullet to check the powder. It sounds/feels like there is powder when I shake the case. I can take pics of the case/round if it would help. |
Normally you'd expect the powder to leak out the flash hole... Have you checked to make sure the flast hole isn't blocked? I've heard of some crappy ammo (A-Merc) not even having it drilled. Your symptoms of the primer backing out seem similar to that... |
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I couldn't find my puller, stuff still in boxes from last move, so I used some pliers to remove the bullet. Dumped out the powder and it looked good. Looked in bottom of case and there is no FLASH HOLE. Head stamp NPA 01 I was just reviewing all the negative info on olympic ammo. It seemed the majority of the Olympic problems were with the 62 grn SS109 round. The 55grn ran okay, before this, in my colt but my friends bushy did not like it. It avg 2804.4 fps out of my 14.5 inch barrell while Fed XM193 Avg was 3035.8 fps. I suppose there is a lesson to be learned from all of this concerning Olympic ammo that I should have listened to before this near disaster. |
Yikes... there you go... that would do it every time...
I think I will make a point to never buy any Olympic ammo... |
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