What did I do wrong here?

Brass color looks like a Winchester primer, though some of the foreign ones don't nickel plate the cups either. There have been some complaints about some lots of Winchester primers piercing and leaking like that. The flattening is pretty noticeable, but not unusual by itself. I would switch to something harder like a CCI and see if the flattening is reduced any.

I'll mention also that I've seen primers in loaded rounds go from rounded to flat with the same partial case fill charge, depending whether the powder is forward over the bullet and away from the flash hole, or backward over the flash hole. Tilting the loaded gun forward or upward before coming level to fire will create these two conditions. If you develop a near maximum load always tilting powder forward, then tilt it up for one round during shooting, that could happen.

I've seen many a Garand bolt with rings of those pierced primer marks around the flash holes. It doesn't affect function, but it is annoying, especially on a new rifle.
 
ADClope,
It might be that you have some large pistol primers in your batch of gun show primers. They will blow at rifle pressures. In your load data I did not see the bullet that you were using listed. You may be using a bullet of different construction, that is longer, both of which might increase pressures. If all the loads used the same powder and bullet it is unlikely that the bullet is problematic. I only buy primers in retail distributors that can't be easily mixed with other primers. You should check for load data that uses your exact bullet.
 
It might be that you have some large pistol primers in your batch of gun show primers. They will blow at rifle pressures. In your load data I did not see the bullet that you were using listed. You may be using a bullet of different construction, that is longer, both of which might increase pressures. If all the loads used the same powder and bullet it is unlikely that the bullet is problematic. I only buy primers in retail distributors that can't be easily mixed with other primers. You should check for load data that uses your exact bullet.
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Something similar happend to me and it wasn't a gun show. I wanted to try BR-2 primers vs the usual CCI-200's I use in a load I was working up, but didn't want to buy several bricks until I was sure I wanted to go that rout since BR-2's are almost double the cost of CCI-200's. So I just bought 2x100 primer sleeves. But 4 of the primers in one of the sleeves were CCI-BR4's!!

This was obvious since small rifle and large rifle primers are not the same size. I called CCI and they said this was impossible at the plant because they are made and packaged in totally different areas. So since they were new sleeves, probably some employee at the store I bout them from dropped several and just guessed where they go.


Since you bought them at a gun show and didn't specify how they were packaged, this could have easily happened Since the only visual difference between LP and LR primers is that LR primers are .008 taller. BUT! LP primers are designed to operate at far lower pressures and lighter firing pins.
 
Thanks for all of the help and comments.

I wonder if it'd be worth measuring the primer height tonight after I punch it out. Does anyone know the specified height of a large rifle primers vs pistol? I'm sure I can easily find it by googling it if not.

I'm starting to really wonder now if that's what happened here...
 
The rifle primers are about a hundredth of an inch taller. The problem is their allowable range overlaps. Large Pistol are supposed to be 0.115-0.126" tall, while large Rifle are 0.123-0.136" tall. That said, I think most of the large rifle primers I've measured have tended to be around 0.127" plus or minus a thousandth or two, and large pistol about 0.117" plus or minus a thousandth or two.
 
Alright, I took a minute to measure these primers and they all are in the .130" range, so it looks like they are indeed all large rifle. Here's some more pictures, the flash hole looks fine and well centered, the primer pocket looks fine too best I can tell. The primer however, has a curious looking line running directly down the side of the cup and meets the middle of that burn hole, not sure if you guys can see that too based on the pics?

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McGee... No, not that I am aware of.

Metal, yes, I am using all of them, bought them at gun show, were sold as large rifle primers, no magnum primers, a few mixed brands (obviously appears to be 3 that I can tell). Were all in a CCI Benchrest box, but as you noted, clearly not all are. As far as I know, large rifle primers are large rifle primers with the exception of brand preference, but operationally, they should function appropriately, no?
 
You provided fantastic, detailed microscopic pictures. It shows pretty much what I was expecting.

There is no explanation for that crack and pinhole occurring unless the brass is absolutely faulty. There was a crack or wrinkle in the brass of the cup and a very small weakness at the point of curve. That weakness was enough for the gasses to pop through, probably before the bullet even left the case, and that resulted in a long lasting intense flame. It burned that hole, rounded off the edges, burned the steel.

You have a split around the edge of the cup and the split in the wall, and good brass is far too flexible to allow that to happen.
 
Yes, excellent photos. Amazon has inexpensive USB microscope cameras that will do that.

Note that the head of the primer is pushed out wider than the rest. That is called mushrooming. I didn't see it clearly in the OP photos, but it is a definite pressure sign, so you are running at pressure that is too high for that primer. It may not be too high for some other brand with thicker cups and plating reinforcement, but you definitely have either excessive headspace or excess pressure for that one.
 
As far as I know, large rifle primers are large rifle primers with the exception of brand preference, but operationally, they should function appropriately, no?
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No. Other than the expected bang when you pull the trigger, primers can be quite different.

You bought a "mixed lot" of primers at a gun show, from someone who could (or would) only tell you they were not magnum rifle primers, right?

In effect you know nothing about what they are, other than that they are large primer size.

The long standing reloading advice to drop the powder charge and work back up, carefully when ever you change components applies to primers as well.

You have 3 different brands there (at least) and POSSIBLY not all the same type (rifle, pistol, magnum...) Relying on what the guy at the gun show said is relying on hearsay.

Primers are the one component we cannot test before use. Using mixed brands is literally using 3 different loads. Maybe they'll all be similar, and safe, maybe not.

I've never personally seen a primer fail like that one, but I can see how it could, if the cup was defective in just the right way.

When you use up (or throw out) that mixed batch, I would recommend only buying primers in their original packages, from recognized makers of long standing. That way, if one does fail, at least you know who to complain to! ;)
 
Primers are not all created equal. In this post I won't make the case that any one is better than another. But they are quite different by brand. Here are a few of the differences.

CCI has thicker/harder cups than the rest, they won't show pressure signs as quickly or even at all sometimes. They are middle of the road in terms of "hotness" . CCI is my brand of choice. Oh and they tend to be slightly bigger than some brands like remmington such that if you use CCI, you may not be able to switch back because the pockets could be too loose.

Federal are generally fairly mild, a bit softer but consistent. Many match shooters use federal

Winchester are generally the hottest primers. You would absolutely need to adjust your load if you were operating near max pressure with Federal primers and decided to switch to Winchester.

Remington are a bit softer and smaller but middle of the road in terms of hotness.

Wolf are a bit hotter, but not as hot as win.

So there you go, deminsional differences, different hardness, and some are hotter than others. Other than that they are identical.
 
The thing i keep coming back to in my head is his POI was 4" higher then the other rounds fired . Im not at home where i can plug that into a ballistic calculator . What pressures will cause ghat much of a poi shift . It would serm it was a over presdure round to me rayher then just a soft primer cup .

Then there's the fact he has no idea what kind of primer he used . He very well could have used a mag primer with a light bullet hold could have pushed the bullet out jamming it into the lands before the powder really took off . Unclenick could that have caused the pressure spike . He is was using superformance a slow for caliber powder .
 
ADC

That looks like the primer failures that were occurring with Rem 7-1/2 primers,
several yrs ago. There was numerous photo's posted and they looked the same as you posted.

I know that when the info came out, along with the lot numbers for the defective primers, I had a 1000 of the lot number that was bad,
I called Rem and they sent me a return shipping label and I received new replacements etc.

I believe that primer was defective, because of the line down the primer wall,
when the bad primer photo's were posted, there was several photo's that showed the same line on the fired primmer, and new primers that were unfired etc.

IMHO,
I would get new primers, which should stop that problem.

The photo's of the primers shows that those are of mixed lots etc.
I would not use them, at least the brass colored ones.

You might want to check the brass colored ones and see if any of the rest of them show a line down the primer walls, that would confirm what you have shown etc.

Tia,
Don
 
I'm going to chime in and suggest telescoping could have been a factor here since I haven't seen it mentioned yet.
Hornady brass is notorious for having short headspacing, leaving excess room to stretch the brass to fit the chamber. Usually the primer is the path of least resistance so it gets blown out of the pocket before the case stretches and reseats it. Sometimes it doesn't reseat completely and falls out when you extract it.

I think the primer telescoped here and cracked when it hit the bolt face causing the gas cutting there. Just a theory. Considering I didn't see any extractor swipes on the brass, I'm guessing it wasn't too hot.

Sent from my SM-N920V using Tapatalk
 
Hornady brass is notorious for having short headspacing,
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I will assume you are saying Hornady brass is shorter from the shoulder of the case to the case head than other brass. And I always wonder why a reloader does not measure before and again after. I off set the length of the chamber with the length of the case from the shoulder to the case head. To do that I have to have cases that are too long to chamber.

And with the very fine pictures I have to agree with Unclenick; the primer looks like the primer was protruding from the pocket and was not supported. I know no one is going to ask; "How could that happen?", but there is a chance that one got away from you and went unnoticed.

F. Guffey
 
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