Friend of mine sent me this picture today.

He loaded 40grs of IMR 4350 in Win brass with a Win primer under a 160 gr Hornady RN bullet. The brass has been fired 3x.

The rifle is a recently manufactured original chambered Model 70.

What do you think caused this?

Looks like the primer cup was damaged in the seating process.

I would have said that pressure may have been a contributing factor but, according to the Hodgdon's site, 40 grains of IMR 4350 is the starting load for this particular bullet. Barring a bad primer, my guess would be a loose primer pocket and/or a primer not seated deep enough. If your friend hasn't already done so, I would be checking the bolt face to make sure it is not damaged.

I had a bad batch of primers once that occasionally did that. There was a weak spot in the primer cup where the gas was able to leak through.

that's gas cutting in the extreme.
when he punches the primer he will see more evidence of what happened.

Just a bad, defective Winchester primer. Switch to Federal or CCI. I'm sure it cut the bolt face a bit, but that won't hurt anything. usually.

defective Winchester primer.

Must be from an old lot. A few years back, there were many failures. Winchester replaced primers and repaired bolt faces.
Check bolt face for pock mark. Looks bad, but ok to keep using rifle.
http://s338.photobucket.com/us...r%20Gas%20Leak/story

Back in the '80s and early '90s Remington put out several lots of large rifle primers that did that exact same thing. I don't remember if anyone actually confirmed how they managed to produce them with those weak spots, but when they failed they looked like the picture above.

He was using Winchester primers.

For a starting load the primer looks pretty flattened and there seems to be a little cratering around the pin strike both indicating pressure right up there but maybe it's just the photo. If pressure is all okay then I too would concur a faulty primer or batch of them most probably.

quote:

Originally posted by dpcd:
Just a bad, defective

Winchester primer. Switch to Federal or CCI. I'm sure it cut the bolt face a bit, but that won't hurt anything. usually.

Yup, BTDT.

243winxb. i had this happen with a starting load in a newly built Gre-Tan rifle. how did winchester go about repairing the bolt faces?

I can guarantee you that Winchester, or whatever is left of them, is not going to repair anything pertaining to a hand loaded cartridge.

Replaced bolt , i should have said.

Google "defective winchester large rifle primers"

Win did replace some lots of primers that were defective.

had Winchester LRM primer do that but not to that extreme!

A loose primer pocket will let gas escape and may looks similar.

When deprimed, the side of the primer may show damage.

It is also possible that when the primer was pushed out the last time, the decapper missed the primer hole and pierced the side of the primer pocket. BTW, just because your friend thought he was loading the described load, doesn't mean he actually did. The fact is there is a lot that can wrong when reloading and ones mistake is usually not discovered until some damage is done; your photo shows all the signs of an over pressure load. Again, best to remove the spent primer and see what it looks like.

Winchester produced some defective primers a while back. I don't think they did a recall but they would replace them. I have 5k of their large pistol primers that do that even with mild loads in the .45 auto. If you search the 'net you can find lists of lot numbers of known problem primers. It is not much of a problem in low pressure pistol loads but in a rifle it could do some serious damage to the bolt face.
C.G.B.

That looks like a hot load to me. There is no radius left at the primer edge. Definitely a flat primer.

Hot load, primer flow into the firing pin channel, as said above.

The pockets may expand after a few firings. It may take as many as 5.

I don’t buy that this is necessarily an especially hot load that blew primers and caused flow into the firing pin channel.

I have tested the “pierced primers due to high pressure” hypothesis and, in my case, found that the same load, shot in the same rifle, showed vastly different results with 3 different primers. With CCI primers, I got primer flow and a pierced primers; with Tula primers, I got no pierced primers and modrate flow; with Federal Match primers, I got no pierced primers and minimal flow. Again, same rifle, same load . . . only difference was which primer I used.

Increased primer flow can occur due to sloppy but in spec tolerances. If you have a fireing pin whose diameter is on the low end of the spectrum of tolerances, and you have a firing pin channel that is on the high end of tolerances, you can get primer flow, espcially if the primer is soft.

I’m not persuaded that the “loss of primer radius” in the picture is much at all. I used to get flattened primers in an old 8mm Mauser. They were really flat — as in they covered the groove between the primer and the brass surrounding the primer pocket with loads that were slightly above minimum (the weaker factory loads pushed the primers out of their pockets and after firing they were quite proud). I do not recall any flow. (This was in the distant past, when I was 14. Now, I can only say DOH! I should have had a gunsmith check it out. Fortunately I’m still alive and have all my parts.)

I’m struck by the gas escaping around the primer. That sounds to me like a failure of the primer rather than anything else. If it is true that Winchester produced faulty primers, that would be the explanation to me. A soft primer, or one whose diamter is slightly less than it should be, might cause that. Or one that is irregular in diameter.

JFWIW.

normally i would say "this isn't the weight he THOUGHT it was" .. but the face isn't all marred like other cases i have seen in high pressure loads --- but when i've seen primer failures, they generally aren't all "flowed" .. or, as I call it once deprimed "Top hat" .. when you pop them out, they kind of look like a top hat, and the size and shape of the brim -- nevermind, it's obvious

could be a REALLY soft primer that fired and mechanically failed

I've had one primer in many years of reloading and shooting that had a pin hole leak in the radius of the primer. Not Winchester. I'd guess just a defective primer cup. Mine didn't cause gas cutting on the bolt but did leak powder gases back at my face.

Yep. Hot load. The primer firing pin hole is even ob-longed.

The primer is clearly defective it was seated with a dent in the primer, you can see the hole and the spray from the hole itself that Vs outward..knock it out and reseat a new primer and see if it is snug, if not toss it..or just toss it anyway, that's what Id do...

If it were pressure etc it would not be so located in one spot from the hole it would ring the whole primer along with an indention on the case heads brass portion, Some call it a shiney spot or scrape on the case head. pressure would have closed upt the space between primer and case if pressure was the problem, and probably a more flat primer. There is some cratering of the primer but that's to be expected with the incident, and back thrust caused by the leak from primer crack not the firing pin hole...Also the primer indicates your firing pin is a tad too long and that alone can cause cratering.

Some guns crater from a too large hole in the bolt face or a too small firing pin and should be bushed or just disregarded, depending on your mental approach to such things.....Its nothing to worry about IMO, most of my old Win. have cratered firing pin holes in the brass with the mildest of loads, sometimes caused by a small amount of headspace, pretty common, and one firing eliminates that as the case is fireformed at that point and the problem has fixed itself unless you fully resize the case again to factory specs.....Neck size it only as long as you can then full length resize and fire form it once more..Helps to anneal these cases but may be cheaper in the long run to toss the old brass and start over..

Did he tumble the brass. Could have been a bit of media in the primer pocket that got crushed during seating of primer and caused uneven seating & a gap.

Poor quality primer is another option as already suggested.

I battled this same thing. It's most likely a bad batch of winchester primers....That was my issue.

Thanks Ray. "Dent" was the word I was looking for when I posted but I couldn't think of it.

FWIW, I agree completely with your assessment.

No, it wasn't pressure, it wasn't brass, pockets, seating. It was a bad Win primer. This has happened before, with them.

quote:

posted 07:loose primer pocket will let gas escape and may looks similar. When deprimed, the side of the primer may show damage

yep.. loose primer pocket, when a case has been loaded 4 or 5 times I dont use WLR primers. I use CCI or fed. I also had this happen Winchester primers are not as thick as they once was. I load win. primers up to 4 times with new brass.. how many times has that case been loaded.?