Tossing this one out to the Internet to see what sticks. I realize this is not exactly reloading, but it relates to reloading issues more than any other forum. I was sighting in a new gun today, Using factory loads (I'm gonna not name the manufacturer, but they have an excellent reputation, and make higher end ammo) had a primer blow out from a factory load. Anyone else ever have a factory load blow out a primer? Case looked fine otherwise. Flash hole looked good, still sharp and round, so no brass flow. Case extracted easily, I didn't notice it at all different from other rounds, bolt handle wasn't at all sticky. Thoughts? Ideas? I've tossed some ideas around with my dad, and a local gun shop full of the usual types who hang around gun shops...and lots of thoughts, but all are pretty out there. So let's add some more out-there ideas. Random fluke is currently the leading contender.

What exactly do you mean by "blow out" ?

Primer blew out of the primer pocket completely. Full separation. Extremely violent decapping during firing. The thing old timers would say "back it down a few grains"

Oversized primer pocket from the factory, made it past quality control.

Will a new primer seat? (That'd be a good check on craigster's thought.)

Most definitely! The primer pocket is now way, way oversized. By about 13 thousandths or so. Heck, a primer will rattle in there now. When a primer blows, the pocket always gets much bigger.

There was a time when Norma factory ammo was considered hot. In a tight chamber would it blow primers?

I had a strange experience with a 358 Win Factory ammo - Winchester brand.

I was shooting a few rounds at the range. Ejected a case and tried to load the next one and it would not chamber. Tried everything and nix. Looked down the barrel and it was dark.

I went home and used a cleaning rod and had to firmly tap out the bullet which was stuck at the throat. I checked the empty cases and sure enough one was clean as new with a fired primer! Obviously it had no powder and only the primer flash had moved the bullet into the throat of the rifle.

Brass failure. Soft, maybe annealed, case head fired at normal pressure. Doubt loose/oversized primer pocket prior to firing.

As with any thing manufactured stuff happens.

It is amazing that with the billons of rounds made that this kind of stuff doesn't happen more often

There are people who always want to turn there rifles and cartridges into something they are not.

Don't know how many times I have heard that a 06 can be a 300mag ect.

If I want more power I buy some thing bigger.

If the cartridges have been subjected to heat as on the dash of a truck and subjected to vibration of driving for any period it can change the structure of the powder and thus the burning characteristic. The cartridge may look fine but the power granules can degrade.

Joe

quote:

Originally posted by Joe Henderson:
If the cartridges have been subjected to heat as on the dash of a truck and subjected to vibration of driving for any period it can change the structure of the powder and thus the burning characteristic. The cartridge may look fine but the power granules can degrade.

Joe

No. If the cartridge was in the sun (heated) right before being fired, it could happen. I was shooting some 22-250 ammo and one round blew a primer. I found that if I let the cartridge lay on the bench, in the sun, it would blow the primer. Simply laying a towel over the cartridges keep them cool enough that the resulting brss looked entirely normal. FWIW, it was summertime.
However, rattling around in a glove box or on the dash will not degrade the powder. Think about how much all ammo is vibrated by plane, train, and truck on its way to market. Even at the factory, the final polishing is done in a tumbler.

It was a bit warm yesterday. About 92 when I started, about 102 when I was rolling home. But the rounds, the rifle and myself were all in the shade the entire time. I let the barrel cool every third shot to where it felt the same as the shooting bench. The ammo wasn't some special custom order, it was factory ammo ordered from Midway last month (with very fast delivery on their part, it sat in my air conditioned house until I shot it) so it wasn't me trying to cram magnum powder loads into a case, it was standard spec ammo.

Let me guess.....WSM?

If I'm wrong....never mind.

quote:

Originally posted by Bigjimttu:
Anyone else ever have a factory load blow out a primer? Case looked fine otherwise. Flash hole looked good, still sharp and round, so no brass flow. Case extracted easily, I didn't notice it at all different from other rounds, bolt handle wasn't at all sticky.

Since there were no excess pressure signs other than the enlarged primer pocket, I think it is safe to rule out that factor. To me the cartridge case looks like the culprit. I don't see how the primer pocket of a cartridge case could be enlarged by .013" with no other pressure signs, unless there was some fault in the brass itself which allowed it to do so.

There was no mention of the shot: did it hit the target, did it group with the previous shots, was the shooter aware of anything untoward happening before opening the bolt?
Was the primer pierced, was there any gas blowback through the receiver? All these questions need to be answered.

A customer bought a box of .270 Win by an old respected manufacturer a couple of years ago. Came back a few days later and showed me 10 of the rounds he had fired. Six were missing the primers. Gas jet cutting around primer pockets on all. Cases heads showed brass movement into the ejector notch and stampings were flattened. Ammo was replaced by mfg with no explanation.

Not a WSM.

Shot was more or less on target, it was a sighting in sorta deal. It was generally consistent with the previous shot. Primer wasn't pierced, and other rounds looked ok. Didn't feel anything odd, bolt face was slightly dirty, but not excessively so. Cases all measured very close, even the one with the now very, very large primer pocket tiny extractor scuff on the case, but I had to look under magnification to see it.