Primer "backfire"!?!?

[editingfx]

OK, this was weird... my son shooting my M&P Pro 9mm, using some 115gr plated over 3.8 Clays with either Federal or Winchester primers. *Might* have been magnum pistol primers, those were all I had for a bit. ANYWAY, we're about 70 rounds in, and there's a sound like a squib load (yeah, I know 1st hand, as I've made some by accident). So we check, and the bullet hasn't even come out of crimp! Looked at the primer, and the outer base is blown away! Only the center is left. Still fully seated. Get home & pull the bullet, there's a full load of powder, nothing blocking the primer flash hole. Deprimed, and only 1 primer came out (thought maybe somehow I'd missed the deprime & squashed a 2nd in the hole... nope.)

Any ideas?

 

[ReloaderFred]

If by the "center is left", you mean the anvil, then that is truly strange. For the cup to depart, it means there had to be room for it to back out of the primer pocket between the chambered case and the bolt face. This would indicate one of two things to me. Either an out of battery detonation of the primer, or a serious headspace problem.

If it was an out of battery detonation, and the powder didn't ignite, you've used up your luck for the year. Don't waste your time buying lottery tickets, since your luck bucket is now empty.

If it was a headspace problem, there should be other indications, such as problems with other rounds, too short a case, etc. Also make double sure it wasn't a 9x18 case, or even a .380 case.

As for getting a second primer into a primer pocket, I don't think even Houdini could have done that. It would involve something like a 2 1/2 pound hammer and a large anvil to accomplish that feat.

There's something else going on here and it needs to be investigated. You're the only one who can do that, since you've got all the evidence in hand. Take a close look at the firearm and how it functions. Also take some measurements on the offending cartridge case. Somewhere in there is the answer.

Hope this helps.

Fred

 

[GP100man]

was the primer upside down & the pin hit the anvil & popped it????


GP100man

 

[D. Manley]

was the primer upside down & the pin hit the anvil & popped it????

My thoughts as well. If this wasn't the case, how did you deprime the case with the center gone?

 

[editingfx]

Yes, I did mean to say that the center portion of the "face" of the primer (the flat center portion where the pin strikes) was remaining. The outer rim, where it curves down into the cup, was blown out, all around the edges of the cup.

All other rounds fired (from same batch) were fine.

I pulled the bullet yesterday (to check for powder & primer hole), so don't know the OAL, but if it was +/- more than about .1", I would've spotted it in my load process. (They go into a plastic case, and when the case is full, I carefully eyeball the lengths and primer seating as a double-check.) When I pulled the bullet, using a kinetic hammer, all that came out was the boolit & powder, so my conclusion was that nothing was blocking the flash hole.

Checked the case, it was a regular 9x19.

Primer was right-side in, as per my loading check above, and afterwards the flat "face" of the primer was facing out.

Finally, I was very near my son when he shot that round, and there had been at least several seconds since he shot the previous. I immediately stopped him, told him to remember that sound, and checked the gun. It was in battery. Racked the slide, out came the cartridge in question. Head-scratching ensued.

 

[loadedround]

For what it's worth I saw a similar situation with a 38 Spl case many years ago and it did look like the primer was seated backwards. The shooter was using the most common progressive presses of the time to reload ammo(wasn't a Dillon and it wasn't me LOL).

 

[P51D]

Editingfx - any way you can post pictures of the primer and casing?

P51D

 

[editingfx]

any way you can post pictures of the primer and casing?

well, I just dug through a big black trash bag looking for 'em. you know how SMALL primers are in a 55 gal black trash bag??? luckily it was about empty, so found the case, but I could only find the anvil of the primer... the rest was gone. so I didn't bother scanning that. here's the case:

 

[The Bushmaster]

If you ever wanted to know what happens when you do not inspect cases after priming. You don't have to ask anymore...editingfx knows...

 

[editingfx]

when you do not inspect cases after priming

But that's the thing - I do! Like I said above, when the loaded round comes out of the turret, it goes bullet down into a plastic case. When those 100 are done, I hold the case up to eye level & look at comparative OAL (rough, of course) and (mostly) primer seating. It's very easy to see if any primers are high, etc.