Random primers penetrating

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Shimitup

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EDIT: (Pierced is the P word that my brain couldn't find) This last week I've been working up some loads for a new AR build, having just dumped my range brass out on the mat to sort I realized I've been getting a few primers punched through. I would appreciate your thoughts on resolving the issue. The nickel plated ones are all Federal 205m, loaded with 55gr bullet over either 23gr of H322 or 26.2gr of BLC-2 for velocities of 2630 and 2730 respectively. No signs of excessive pressures, plenty of room to ramp these up but for the primers. The cases primed with the old copper plated R71/2 were thrown in for comparison, they were loaded with 26.7gr of W748 at 2890 fps for comparison. I know Federals are softer but never had the issue with my Ranch Rifle, I'm sure you can see the ejector dents from previous firings from that gun tossing deadly projectiles to the right.

Thanks!
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Your using some very old LC brass which is know to be considerably less volume than current LC and commercial. So this is probably whats causing the high pressure.

With that said Federal primers are know to be softer and will show pressure signs earlier. Rem 7 1/2 and CCI 41 is what I use in most all my 223 & 6.5 CM. Have not used the powders you are using except the H322 and did not get the results I was looking for.

Check your FP on your rifle. It may have been damaged from the pierced primers, a piece of metal stock to it. If so you may be able to clean it up if not real bad. If this is the case it will cause pierced primers. Don't use the Fed 205m primers on a AR. You will get slam fires. I did a test with my 6.5 CM with a JP Enterprise HP bolt, it would set the GM205M off as soon as the bolt dropped. If your not familiar with the HP bolt, it has the smaller 1/16" dia pin and has been lightened and designed to keep from blowing gas in your face on primer failure. All my 6.5 CM brass is small rifle. Did fine with the GM206MAR primers.
 
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First, reduce the powder charge.

Pierced or Blanked Primers. -------------------------------------------------------------------------------- 1. Check the firing pin, it should have no gas cutting or deformities. 2. Firing pin protrusion should be checked. Internet search shows .055" to be about right for bolt actions. For an AR15., Colt and S&W M&P 15 armorer manuals uses a GO dimension of .036" and a NO-GO dimension of .028". Check with a gun smith as each firearm IS different. 3.The firing pin must stay in contact with the primer on firing. A weak hammer spring on an AR or a weak firing pin spring like on a Rem 700 bolt action will let the firing pin rebound on primer piercing when the hot gas pushes the pin backwards. 4.If the hole the pin sits in is to larger in diameter, the primer flowes back into this hole till the center of the primer separates and fall into the action or travels into the firing pin area. Bushing the firing pin hole (bolt action) will fix this. Or you may want to try a magnum primer with a thicker cup. Military ammo may have a crimp that needs to be removed before seating a new primer. The crimp is removed by reaming or swaging the primer pocket. Swaging may be needed here so the prime can be seated lower in the pocket. Flush with the case head to .008" below. High primer = misfires & pierced primers. The CCI 400 is thin & soft, change to a mag. or Rem. 7 1/2 primers. If you fire a primer, no powder/bullet in the case, the primer will back out of the case equal to the head clearance of the brass.
 
I would not think that I would have excess pressure with no other signs of it than pierced primers, velocities are low to moderate even for the 16" barrel. I shot some Herters (Lake City) on the same outing yielding 2950 which is actually hotter than I care to go with my handloads, yet no signs of excess pressure. My firing pin extends .034 and has a perfect smooth radius and the pin hole is tight.
 
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None of the primers show signs of excessive pressure. They are not flattened in the least bit. Unless they are incredible tight pockets. One sign of excessive pressure will move the primers back against the bolt face. You will see the primer not only flattened but start to flow into the firing pin hole. The depth of the firing pin strike looks deeper than it should. I’d try several brands of primers loaded into empty cases and compare the results.
IMO the firing pin or its spring is suspect.
 
This last week I've been working up some loads for a new AR build, having just dumped my range brass out on the mat to sort I realized I've been getting a few primers punched through. I would appreciate your thoughts on resolving the issue. The nickel plated ones are all Federal 205m, loaded with 55gr bullet over either 23gr of H322 or 26.2gr of BLC-2 for velocities of 2630 and 2730 respectively. No signs of excessive pressures, plenty of room to ramp these up but for the primers. The cases primed with the old copper plated R71/2 were thrown in for comparison, they were loaded with 26.7gr of W748 at 2890 fps for comparison. I know Federals are softer but never had the issue with my Ranch Rifle, I'm sure you can see the ejector dents from previous firings from that gun tossing deadly projectiles to the right.

Not every barrel is the same, not every chamber is the same, and not every primer is the same. Loads developed in my Wilson barrel, NM AR15's, blew primers in my Krieger barreled Space gun AR15. Wilson barrels are button rifled, Krieger are cut rifling, and Krieger barrels are tight regardless of their caliber. And, when Winchester went from the nickle (Customer service said zinc) plated primer to the brass WSR, (about 1999) loads that never bothered the nickle WSR pierced the brass finish WSR and ate up firing pins. Winchester said they made the primer more sensitive by making the cup thinner. That is bad, bad, bad, for service rifles.

Do what every AR15 service rifle eventually learns: cut your loads by a 1/2 grain till you stop having pierced and blown primers. My Krieger barrel loads were at least 1.5 grain less than my Wilson barrel loads, and I had to cut the brass WSR even more. Eventually I shot up all the brass WSR and went back to my old loads with the great and wonderful CC#41 primer, which is the only appropriate primer in the AR15. It is made to the military sensitivity specs. I had an in battery slamfire with the brass WSR, on first relay, my scorer on second relay, his AR15 slamfired also in the standing stage with Federal match primers. Slamfires are rare, but having your gun go bang when you did not want to makes a big impression to the guy behind the muzzle. A friend of mine, at Camp Perry, could have been seriously shot on the firing line by a Junior. It was during the standing slow fire stage. He said the junior on his relay was handling his rifle dangerously. I think it is possible the kid was holding his AR in line with the firing line when he was loading the thing. I have seen that by another shooter, the guy raised his rifle up to his face, put a round in the chamber, and chambered the round with the rifle parallel to the firing line. I think that was insanely dangerous to his face, and if the rifle discharged, anyone down range of his muzzle. I think that is what happened with the Junior, or at least, the muzzle was not pointing downrange. The kid's rifle slamfired and the bullet passed between Bud's left arm, extended holding his rifle, and his body. Just a little more weaving and the kid would shot him through the body.

I used to get into arguments all the time with trolls who absolutely insisted rifles did not slamfire due to primer sensitive. Thank goodness for the internet, I could bury the troll in posted accounts, not that it really changed the position of the troll. Some trolls are just out to kick the ant heap over and watch the ants scurry. These master manipulators are out there, and they have fun messing with the ants.
 
Thanks for the feedback Slamfire, I just hate to reduce loads just to use up fragile primers. I'm leaning toward just abandoning the Federal primers and using a stock of nickel plated WSR's that I still have, in the long run I may well go back to the Rem 7 1/2 which BTW I've noticed that are no longer copper plated and have gone to a tripod anvil. I betchya that belies the fact it's been a while since I stocked up on small rifle components.
 
If you have a known good ar I would swap bcg and see what happens.
As this is my first build I haven't another to swap, I'm somewhat doubtful it would matter as the firing pin protrusion is perfectly centered between go and no go at .031" and is perfectly smooth and radiused.
 
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