Is this normal, over pressure round maybe?

[gulogulo1970]

I was shooting Corbon 9mm 115gr +P in my S&W 940, a J-Frame 9mm revolver, and it locked up. This is nothing new because it is kind of finicky in what it will shoot, example Blazers expand and lock it up. Anyway, it locks up I take it home and find that the primer looks to have expanded into the firing pin hole.

I've attached a photo of the case. Is this a common thing? I've been shooting for a while and have never encountered this before. I know brass flows when under extreme pressure is the primer material not as tough?

 

[SDC]

Definite cratering, but Cor-Bon is loaded to higher than normal pressures to begin with; I just wouldn't use THAT ammo in THAT revolver anymore. It would probably work just fine in a semi-auto, if you have one to try.
And, yes, since the primer has to be thin enough to "give" when it's struck by the firing-pin, it's made out of softer/thinner brass.

 

[redneck2]

From the photo, it appears to exemplify primer cratering. The only other possibility would be excessive clearance around the firing pin.

I would contact Cor-Bon. I suspect they'd be interested in this.

And no, I personally wouldn't fire any more.

 

[grimjaw]

gulogulo1970, I had that same thing happen with a S&W .38 once. The rounds were hot, and I stopped using them after just a few.

jm

 

[bogie]

Yeah, with ANY (rifle or revolver, so let's not move this post, okay mods?) cartridge gun, you wanna keep an eye on the primers. That it some VERY high pressure there.

I shoot my BR rifle hot enough to regularly see craters like that, but then it is a custom action and a nice big barrel.

What I'd guess happened here: Did you fire some jacketed rounds after firing some softer lead? What may have happened is that you've got a bit of a bore constriction which is comprised of crud (same thing can happen in rifle, okay?), and it'd probably be a happy time for the little revolver if you'd take a nice bronze brush and some good solvent, and go to town on both the cylinders and the barrel. DO NOT use stainless, and take your time.

 

[wally]

As a reloader, if I get primers that look like that I'd throw the rest of the lot away and reduce the charge weight 5% at least before trying again.

Cor-Bon wants a reputation for having the hottest factory ammo, they can have it, but I'd not buy any more of that ammo for sure, maybe try it in different pistol, could be OK in a gun with different chamber tolerences.

You are getting early warning that your hand gun might be on the road to becoming hand grenade with that particular ammo if you proceed.

--wally.

 

[gulogulo1970]

Thanks for the responses.

Quote: "What I'd guess happened here: Did you fire some jacketed rounds after firing some softer lead?"

No, it was my 16th shot. I was seeing what my little gun liked. I shot 10 Hydrashocks, it liked those shot point of aim and no sticking. Then I shot 5 115gr +P Corbons and had some stiff turning of the action and extraction, didn't check the primers. Then I loaded 5 more and on the first shot=frozen gun, done for the day.

Got it home and with a cloth and a rubber mallet got the revolver open, couldn't think of another way to free the cylinder. At that point I saw the primer and saw something was really wrong. I've never shot anything without a jacket in the gun.

The recoil and blast was more akin to shooting my Ruger Sp-101 with 357 magnums.

I've attached another photo showing OAL of the Corbon(far right) compaired to a WWB 115 gr JHP(Middle) and an unknown weight(probably 124gr) Hydrashock (far left). The Corbon is shorter than the WWB by a good amount, sorry I don't own calipers. Could I have gotten rounds that have bullets that have been seated too deeply?

Oh, and don't worry I'm done with Corbons in this gun.

 

[Gifted]

Lighter bullets tend to be shorter for the same type(Only a few ways to mess with wieght). I would consider the possability of a compressed load. Call Corbon, ask them what the over all lenth should be, and measure it. That'll be the best way to tell.

 

[B36]

The 940 is famous for problems with hot ammo. Nothing really new. The Cor Bon is fine in Ruger 9MMs. Not an ammo problem.

Do you have a 940 or a 940-1? Firing pin was changed for the 940-1. Supposed to help the problem you are having-- gun discontiued in 98.

Good luck.

 

[Walkalong]

Notice that these "cratered" primers are not flattened whereas the "OK" primers are flattened with no sign of cratering. Think about it.

 

[Ultima-Ratio]

Are You?

Using moon clips?

 

[gulogulo1970]

Mine is a 940-no dash. Didn't know they had firing pin problems. I thought they only had expansion issues in the cylinder.

I guess I'm just going to have to find out what it likes by trial and error. So far I've found three factory loads it shoots well and two it dosen't.

 

[bpisler]

That's a lot of cratering with no flating of the
primers,how easy do the empty's eject?

 

[gulogulo1970]

"That's a lot of cratering with no flating of the
primers,how easy do the empty's eject?"

Had to hit the ejector rod with a wooden handle of a hammer to free it.