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Protruding Primers

Posted By: Rob M

Protruding Primers - 03/23/15 05:34 PM

I have about 150 rounds of .308 ammo that I purchased from cheaper than dirt, but every round has a protruding primer after firing. What is causing this?

Posted By: Dave3575

Re: Protruding Primers - 03/23/15 05:37 PM

those are way over pressure. I would not shoot anymore of those based on the primer and ejector marks.
Posted By: ChadTRG42

Re: Protruding Primers - 03/23/15 05:46 PM

It does look a little hot, but not 100% sure yet. What rifle are you shooting these out of, and what bullet is it? Or what are the specs on the ammo?
Posted By: redchevy

Re: Protruding Primers - 03/23/15 06:14 PM

Im with dave. Shiny sots on case head, and primers, looks like hi pressure. Any extraction problems.
Posted By: Rob M

Re: Protruding Primers - 03/23/15 08:17 PM

The are 178 grain Amax's from right to bear ammo, which is now Beck ammunition. I've been shooting them out of my LR-308 with no problem.
Posted By: ChadTRG42

Re: Protruding Primers - 03/23/15 08:42 PM

Most AR-10 gas guns will leave a shiny spot on the case head. So, you can not go by this for pressure signs 100% of the time. The primer is protruded more than normal, but can be from the the release of the bolt too soon and allowing the bolt to come back with pressure still in the gas system. Does it do this with other brands of ammo? If this is the only ammo that looks like this, then it could be pressure signs. If they all look like this, then it's the functioning of the rifle and not the pressure of the round. AR's can be very difficult to determine a high pressure round. Also, do you know the speed of the 178 A-max (in your rifle, not what's written on the box), and what barrel length you have?
Posted By: Rob M

Re: Protruding Primers - 03/23/15 08:54 PM

I fired some Winchester ammo I had with no issues, so I'm assuming that it's an issue with this brand. I haven't shot them through a chrono, so I have no clue what the velocity really is. I only have their spec sheet that lists them at 2650 FPS out of a 24 in barrel. My AR-10 has a 20 inch bull barrel on it.
Posted By: Dave3575

Re: Protruding Primers - 03/23/15 11:53 PM

Originally Posted By: ChadTRG42
Most AR-10 gas guns will leave a shiny spot on the case head. So, you can not go by this for pressure signs 100% of the time. The primer is protruded more than normal, but can be from the the release of the bolt too soon and allowing the bolt to come back with pressure still in the gas system. Does it do this with other brands of ammo? If this is the only ammo that looks like this, then it could be pressure signs. If they all look like this, then it's the functioning of the rifle and not the pressure of the round. AR's can be very difficult to determine a high pressure round. Also, do you know the speed of the 178 A-max (in your rifle, not what's written on the box), and what barrel length you have?


he's right - i never think about gas systems. That's why he's superchad!

Posted By: ChadTRG42

Re: Protruding Primers - 03/23/15 11:55 PM

Oh, my Dave!! You didn't!!!
Posted By: Dave3575

Re: Protruding Primers - 03/23/15 11:57 PM

I did...

So the one on the far right I see gas leakage too - could that also be the bolt releasing to soon or would that only come from pressure (in a gas system)
Posted By: Beaubien

Re: Protruding Primers - 03/24/15 01:51 AM

I'm in the over pressure camp. I bought some Argentinian surplus ammo and had a similar issue. I would call the manufacturer and see if anyone else has reported issues.

Might pull a couple and weigh the charge. Maybe they will tell you what powder they are using. If not you can tell them the charge weight. Might keep someone from getting hurt.
Posted By: kmon11

Re: Protruding Primers - 03/24/15 05:08 AM

Like the others said could be over pressure the gas system or just pure over pressure but these loads could very well be fine on pressure in a bolt action but not for your gas system. Pressure curves are different with different powders and bullets, the combination in this ammo could have the bolt opening early while the cartridge is still under more pressure and over gassing the mechanics.

Posted By: Rob M

Re: Protruding Primers - 03/24/15 12:27 PM

I guess I need to go shoot a few rounds out of my Rem 700 to see if I'm getting the same issue. The Winchester ammo I shot didn't have any issues, so I at least narrowed it down to this load. I emailed the company yesterday and sent them a few pictures. I guess I'll see what their thoughts are. Thanks for all the responses!
Posted By: Beaubien

Re: Protruding Primers - 03/24/15 06:37 PM

That would definitely help isolate. I did the same with the surplus round and had to beat the bolt open. Only needed to fire one to convince me.
Posted By: Korean Redneck

Re: Protruding Primers - 03/24/15 07:37 PM

Originally Posted By: Dave3575
Originally Posted By: ChadTRG42
Most AR-10 gas guns will leave a shiny spot on the case head. So, you can not go by this for pressure signs 100% of the time. The primer is protruded more than normal, but can be from the the release of the bolt too soon and allowing the bolt to come back with pressure still in the gas system. Does it do this with other brands of ammo? If this is the only ammo that looks like this, then it could be pressure signs. If they all look like this, then it's the functioning of the rifle and not the pressure of the round. AR's can be very difficult to determine a high pressure round. Also, do you know the speed of the 178 A-max (in your rifle, not what's written on the box), and what barrel length you have?


he's right - i never think about gas systems. That's why he's superchad!




Totally not cool. I believe he likes to be referred to IncrediChad instead.
Posted By: ChadTRG42

Re: Protruding Primers - 03/24/15 08:08 PM

BTW- that was from the Rifles Only friends and family competition. And yes, costumes were mandatory!
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