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Posted: 1/23/2010 3:32:22 PM EDT
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I went shooting today with 600 rounds of 17 82 (Barnual) headstamp 5.45 Russian surplus from AIM and had over 30 blown primers, It sucks getting smoke and debris in your face and primers jammin up your action and trigger.
Anyone have any problems with this ammo. I think I got a bad lot maybe! 
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third time. I shot other ammo without any issues. Is there a way to fix or adjust headspace? Not easily. Requires barrel to be moved in trunnion. You might be able to judge headspace with just vision. Remove the bolt from the carrier and rotate it into battery by hand and see how much gap there is from the breach face to the face of the bolt head. There should not be than a couple sheets of paper worth of thickness between the two. On the ammo, there could be some issues with the ammo and the primer pocket being oversized or the primer being undersized. |
| nope I had eye and ear pro. I would clear the jams, open the cover and dump the poped primers. only a couple actually sent smoke and metal flying. It takes me almost an hour to get to my range and I was determined to shoot up that ammo! I was not in danger of blowing myself up it was just unpleasant and dirty. |
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also when a rifle is built from a demil kit isnt headspace already set up from the factory. for instance my gun which came from a demil bulgy kit. I figure adding a new reciever wouldnt affect headspace? In theory you're correct. Removing the barrel and replacing it should not affect headspace. In reality, the barrel does not necessarily end up in the exact same place when it's replaced and the difference between correct headspace and excessive headspace is not great. Every competent builder sets the headspace correctly when the barrel is replaced. |
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also when a rifle is built from a demil kit isnt headspace already set up from the factory. for instance my gun which came from a demil bulgy kit. I figure adding a new reciever wouldnt affect headspace? Correct. However if the rifle is a build with a domestic barrel then it would need to be headspaced appropriately. OP: What kind of rifle? |
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also when a rifle is built from a demil kit isnt headspace already set up from the factory. for instance my gun which came from a demil bulgy kit. I figure adding a new reciever wouldnt affect headspace? In theory you're correct. Removing the barrel and replacing it should not affect headspace. In reality, the barrel does not necessarily end up in the exact same place when it's replaced and the difference between correct headspace and excessive headspace is not great. Every competent builder sets the headspace correctly when the barrel is replaced. I was gonna post this, but PTP beat me to it. That'll learn me to go do homework when there's postin' to be done. 
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also when a rifle is built from a demil kit isnt headspace already set up from the factory. for instance my gun which came from a demil bulgy kit. I figure adding a new reciever wouldnt affect headspace? Correct. However if the rifle is a build with a domestic barrel then it would need to be headspaced appropriately. OP: What kind of rifle? It a Bulgy Kit built on a NDS-2 reciever. It has the Bulgy barrel. I used some ammo that had the 270 82 headstamp with no problems at all, over 1000 rounds! |
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Who built the rifle? You, friend?
When thousandths of an inch can cause a catastrophic failure, i wouldn't trust a factory setting. I had the opposite of this happen to me w/ a WASR. Factory setting = bad headspacing..... It took 300-400 rounds before the problem was noticed. |
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Who built the rifle? You, friend? When thousandths of an inch can cause a catastrophic failure, i wouldn't trust a factory setting. a vendor on the EE had a smith build it. I figure if it was that bad the gun would have blown up by now! esp with over 1000 rounds through it |
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If the primers are simply pierced, this has nothing to do with headspace. The firing pin is sharp or needs to be shortened, It's an easy fix.
I would have stopped and gotten it corrected after one or two blown .mil primers –– They are typically harder/thicker than .com. ETA: Photos will make this thread infinitely more valuable. ETA2: Well there they are! Those are blown primers! Take/Send it back, pronto! ETA3: Headspace shouldn't shift that fast. You would have noticed primer setback or leakage previously, imo. Bad ammo happens. (Also get the heaspace checked –– for the hive's knowledge base. Gas out of the 'user end' is a serious deal. ) |
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I did not see it stated if it was a matching kit.........
I would not think head space has anything to do with it either, you already shot plenty with it !! sounds like the ammo or firing pin is piercing the primers.. take th bolt out and check the firining pin travel and if its sharp like the other guy said. |
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The first photos show leakage, cratering, and blown primer –– All signs of possible hign pressure. Was there any other sign of 'pressure'? Sharp recoil, hard cycling, or brass thrown farther?
If that was my rifle, I'd get my hands on a set of guages, and find out exactly wtf's happening. |
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I figure if it was that bad the gun would have blown up by now! esp with over 1000 rounds through it If the headspace was just short of excessive when the rifle was rebuilt, wear could cause it to become excessive. The proper way to sort this out is to check the headspace. If it's within spec the problem may be the ammunition. |
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Sure it could be a dirty rifle; If you have a bore so badly fouled that the pressure is spiking. Is the bore fouled with metal? Does the chamber have a ring of carbon in the neck area? This is why cleaning brushes are sold.
It's chrome right? Put the muzzle in a can and run a stainless brush through it a few times –– wet with solvent. That will get a lot of crap out. (This is not something you'd do with an expensive target bbl. –– But I do it with hunting rifles every twenty rounds or so to keep the metal fouling in check.) ETA: Get a ballpark headspace by adding tape or sticker plastic to the base of a ctg with bullet & powder removed. When resistance is felt as the bolt rotates closed, peel & measure tape –– or count layers and add the result. It's entirely possible that you have both problems –– Excessive headspace and overpressure. ETA2: Did you have 30 primers 'blown' like the one at the top right in photo? Primer gone / black hole? That's what I call a problem sign –– Keep wearing your protective gear. |
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