Selway Armory 180gr JHP Zombunition

[BEEMER!]

I have experienced these "Fried Egg" primers on several occasions, always with small DAO, compact, hammer fired nines.  I too felt it looked like soft alloy used in the primers, but why does it do it only with one pistol and not all of them you fired the rounds through?

I finally  found that the fired cases that appeared this way were always on the "short side" of the length tolerances and the pistol's chambers were always on the "long side" of the tolerances.  Just my theory.

I talked to Hornady about the matter and they said my theory was one of several possibilities and they would have to have the pistol and ammo to make a  statement of cause.  Not worth the bother.

By the way they always seem to fire fine.

[The_Shadow]

Beemer, I have seen this also from a SA/DA S&W 1006 on 10mm and 9x25Dillon.  It is probable that the case is short or short head spaced.  This can allow a softer strike of the primer as the firing pin tries to push the cartridge forward, it is ignited, the pressure builds, slamming the casing to the rear into the breech face.  That should start the ejection cycle by pushing the slide / barrel backward as a unit till the barrel tilts, this is where the small shear mark happens.  I feel the primer cup is either thin, soft or both to allow the cup to push out as in this case possibly...

When we see firing pin wipe on the primer, the firing pin is not retracted from the primer fast enough, thus leaving a wipe mark as the barrel tips down out of unlock from the slide.  This can be debris build up or weak springs or both.  The easiest is to clean the channel the firing pin and spring apply the slightest amount of oil as a preservative not as much as a lubricant.  We are talking wipe on and wipe off almost dry...This also gives you a chance to check the firing pin & spring for damage.

[BEEMER!]

Shadow  -  I agree with the your analysis.  I had these "fried  egg" primers years ago with a Colt Pocket Nine which was prone to light hits.  It showed up again about a year ago with a Rohrbaugh R9 and Hornady Critical Defense ammo.  I dug the Colt out again and did some testing along with a Kahr PM9.  All the rounds fired fine with the fried eggs only showing up on the R9.  The Hornady cases were all short but in spec and I took all three pistols to my Gunsmith who checked headspace and found the R9 to have the longest chamber.  All the other ammo I was using had longer cases and had nomal looking primers.

The Rohrbaugh is by far the lightest hiiting pistol I have ever owned, but I have not had a single failure to ignite on the first strike.  It still concerns me.

[Intercooler]

I dug the rest of the JAG brass out today. The weird one is on the left and it looks like I lost one. All the rest look okay... 

[doverpack12]

Stopped by the Selway Armory store today.  Its a nice small store with some great prices.  I asked about the Skull Crushing Hollow Point bullet and the young guy working said he was fairly new and wasn't around when they last sold them.  He is going to check into it and hopefully have an answer next Friday when I plan to stop in again and check what the got for the week.

[The_Shadow]

Just so you know the one Intercooler sent me that I tested yesterday had that shear mark on the primer where the firing pin struck it.  Looked just like yours in this picture. 
10mm Selway  180gr JHP   1154 fps   The performance was great and I like the Jag Brass from Jagemann...

[Intercooler]

At least we are repeatable.  What causes this?

[pacapcop]

Im going out Tuesday and will fire off some that I have. Ill be using the 1006 and G20.Shadow,what were firing with?

[The_Shadow]

Here are some cut and paste of what others have stated over at THR...http://www.thehighroad.org/archive/index.php/t-440870.html

SDC writes, "primer wipe", this is where a ring around the firing-pin impact bulges out far enough to get squished or sheared off flat by the breech-face as the pistol goes through its unlocking process, leaving an area that looks like a razor was used to slice off part of the primer (though not usually completely through the primer, which would be bad). If it happens even with factory loads, I'd say it's just something you'd have to live with, but if it's happening only with your 10mm reloads, then there factors in your handloads that you can change to deal with it. Some designs are known to have larger-than-normal firing pin holes in their breechfaces, and this can cause the described effect even with factory ammo.

The Lone Haranguer writes "Primer wipe" is a teardrop-shaped firing pin impression, accompanied by a drag mark (scratch or gouge) following the "point" of the teardrop and leading away from the primer, sometimes into the brass. This is because the firing pin does not fully retract after the round has fired and the slide is traveling back during ejection, causing the case to drag across the firing pin as it is thrown clear. It is not in any way harmful, except sometimes to the case if the primer pocket edge is gouged. Kahr will tell you it is a normal condition for their pistols, even saying so in the owner's manual.

Yes it does occur quite frequently, things that come to mind are, thickness, hardness and plating (to include the process) of the primer cup itself, the flash hole size, internal load pressure and heat exerted on the cup at the time of firing. 

The gun's breech face, firing pin, extractor hold and the tilting of the barrel out of battery has some things to do with it when it is occurring. 

Upon firing, the casing is being thrusted back to the breech face, and the primer cup is being dimpled outward and surrounding the firing pin or striker during the peak pressure phase, as un-lock starts the barrel and slide are moving and the the barrel starts to tilt downward, this action rubs or wipes this raised area against the sharp opening of the hole where the firing pin or striker protrudes.  To correct this a change of primer may be needed as the cups maybe too soft.  When Striker fired pistols first came out most primers were harder and this caused mis-fires as a result.  The primer manufactures made changes (softer or thinner) to the cups in the effort to eliminate these issues.

Bits of the primer cup are sheared in the worst case as we have seen here, the down sides are;
If the cup is cut through completely (rare) some residual gases can be blown back in the breech and firing pin or strike hole.
Tiny bits of the sheared metal can accumulate inside of the firing pin / striker hole and channel...over time this can cause a soft hit or a no hit strike to a primer by adding drag or actually blocking the movement of the firing pin or striker.  Detail cleaning will be needed to correct the issue.

Here is the picture of the recent test of the Selway loading 1154 fps

[pacapcop]

Shawdow,what platform were you shooting out on the zombie rounds?

[The_Shadow]

These were shot yesterday from my S&W1006 5" with the 22 lb recoil spring from Wolff.
They are also from the same lot that was set to Intercooler which he sent for pull-down testing.

[pacapcop]

About 532 ft lbs.

[pacapcop]

Noticed that BVAC now is offering a 165 Flat Nose in 10mm. It's offered on Selway's site. No further specs.

[pacapcop]

Received an e-mail from Selway on the 165 gr flat nose. Ballistics pending.

[Intercooler]

Gel was done today. Just waiting to grab the video.