Help reading a primer, overpressure?

[Glockadopoulos]

I'm going sizing a batch of range brass while the hurricane passes through. I've found a few weird primer strikes like this. Is that a sign of excessive pressure, or just a weird firing pin?

Follow-up question. If it IS overpressure, would you load it up and shoot it if web shows no visual sign of damage and it plunks into case gauge after sizing?

 

[StuP]

I know nothing, so in for the answer. My imagination tells me it's pressure and the primer has flowed back into the firing pin hole.

 

[Greybeard]

I have some similar to this and....
All my reloads, same powder, same charge, same bullet, etc
Shot from 3 different pistols,
92fs, looks good
Glock 19 looks good
Taurus 92 afs looks like what you have.
At first I was concerned about pressure but notice all primer cupping came from the Taurus.
Found out heatspacing was on the high side on the Taurus, but was within limits. Reduced loads, same thing. No other signs of high pressure.
While primers are a good sign of high pressure, it should not be the only thing you should look for.
If the brass sizes okay, no blow outs on brass, pocket still holds new primer tight, and case not stretched, I would load again and fire from my pistol and check.
Just a thought.

 

[avmtdan]

I think overpressure normally flattens a primer out on the outside, and takes the rounded edge off and makes it more of a 90 degree edge. Never seen one pucker the primer strike out like that though. What kind of primers are you using?

 

[Glockadopoulos]

I think overpressure normally flattens a primer out on the outside, and takes the rounded edge off and makes it more of a 90 degree edge. Never seen one pucker the primer strike out like that though. What kind of primers are you using?

These are all mystery brass fired by somebody else. I find normal flattened ones every now and then. I also found some brass with holes burned through the firing pin hole. Not sure what causes that?

 

[Horsehat]

When you knock the primer out check to see if the flash hole is larger than normal. This is definitely not normal even for a high pressure load.

 

[Flashover16]

as mentioned primers are simply an indication of pressure, and possible other problems.
an enlarged primer hole, improper head spacing, a soft metal used in a particular batch of primers, a rough firing pin.
so to judge by a single primer or even a single batch of primers can be misleading.
IF the case web looked good and no cracks then I would reload the brass myself.
then see how things look when its fired with you loads and from your gun.

 

[avmtdan]

These are all mystery brass fired by somebody else. I find normal flattened ones every now and then. I also found some brass with holes burned through the firing pin hole. Not sure what causes that?

Those would be high pressure situations.

If I had to guess as to your bulging primer since this unknown brass and primers would be a blowback style 9mm (tec9, pps43, ar15 in 9mm, etc) where the impulse off seats the brass as soon as the gun fires, meaning the primer has no support against the bolt face but case still has pressure in it. Most guns have a slight delay on when the bolt moves, which allows support for the primer until the pressure in the chamber is bled off by the round leaving the barrel.(glocks, sigs, etc)

Most likely normal operation. I have a tec9 and suomi, will try to run a few through to see how they look.

 

[jeep78]

That looks more like an oversize firing pin opening in the slide. Primer edges would be flat and square if overpressure.

 

[Flashover16]

These are all mystery brass fired by somebody else. I find normal flattened ones every now and then. I also found some brass with holes burned through the firing pin hole. Not sure what causes that?

possibly a bad firing pin, rough or broken tip, not smooth as it should be.