Gotcha, you peeked.

Now that I've got your attention.

During my last range session, one of my cases had a primer that looked like this



What is this? Never seen it before.
My gut says a pressure issue? I fired nine other rounds of this batch with no signs of pressure or anything else wrong.
Been using this load on and off for years with no problems.

Rifle - Remington M700 ADL in 270 Winchester
Remington cases
53gr IMR-4350
140gr Hornady 140gr BTSP
Winchester WLR primers

Thanks
ZM

I have three possible explanations. Guesses really.

Pressure - Either it's a really bad picture, or your whole case head is very swollen. Too much pressure?

Headspace - If the case is swollen, maybe there was excessive headspace?

Primer Deformation - The only thing I can think of that may have caused that is maybe there was a small foreign object between the case and the bolt face, and the firing pin struck that object.

These are just my guesses. I may very well be wrong, but it definitely looks like your case head is deformed in the pic. What caused the mark on the rim just beside the WIN?

too little silicone in the case.

I am guessing also.

If this only happened to one out of nice rounds fired, I would get all of the fired cases and start doing some measuring.

Have these cases been previously fired?
Have they been properly trimmed?
Did this particular cartridge have a hard crimp compared to the others?
I would carefully remove the primer and compare it to others.
Did the bullet get seated too far out or too deep?
Was it difficult to close or open the bolt?

A good micrometer can probably give you enough information to make an educated guess.

If you gather the above information and post it here I am sure that you will get some additional help.

Good luck.

quote:

Originally posted by SD Shooter:
I am guessing also.

If this only happened to one out of nice rounds fired, I would get all of the fired cases and start doing some measuring.

Have these cases been previously fired?
Have they been properly trimmed?
Did this particular cartridge have a hard crimp compared to the others?
I would carefully remove the primer and compare it to others.
Did the bullet get seated too far out or too deep?
Was it difficult to close or open the bolt?

A good micrometer can probably give you enough information to make an educated guess.

If you gather the above information and post it here I am sure that you will get some additional help.

Good luck.

I have Starret micrometer. The case head diameter measures within .0005" of ten other cases I checked at random, including some cases from that session.

Cases are neck sized.

I use a Wilson-Sinclair trimmer. Cases are trimmed .002" under max

I don't use a crimp for 270.

Too deep? Didn't feel any different from the other rounds. I try to stay .015" or so off the lands.

As I recall the bolt cycled fine.

I shot 20 rounds that day. 10 rounds of this IMR-4350 load and ten from another recipe using H4831SC. This was the only funny looking case out of the bunch.

I am going to remove the primer and see if a piece of dirt got into the primer pocket? I clean them out every firing, but I may have missed something.

It should be noted that I am a fussy, meticulous reloader. However I am not discounting the possibility I may have made a mistake.

Steel Slinger:
It's a really bad picture. The mark by the WIN is a smudge. Came right off.

ACRecurve:
Only 100% grade A "Imperial Red-Headed Scorpio' boobs are allowed near me or my guns. No silicone allowed.

Thanks for the replies
ZM

Are the primer pockets on this batch of cases getting loose? If so, it could be that you had gas leak around the primer pocket that crushed the primer much like a leak in the neck area will crush the shoulder.

If this is the case, you should see some soot and perhaps some gas cutting on the bolt face.

Gabe

Poor photo, but it looks as if it is nothing more than the firing pin decided to stay with the primer.

Cause is generally some sort of grit in the bolt.

quote:

Originally posted by ricciardelli:
Poor photo, but it looks as if it is nothing more than the firing pin decided to stay with the primer.

Cause is generally some sort of grit in the bolt.

I'm not gonna win any awards for picture taking.

There was some crud in the bolt face. I cleaned it out. Hopefully that is the problem.

Thanks
ZM

I'll vote for a stuck firing pin. Clean it up and lube LIGHTLY. How can it be a pressure issue
when the dent goes in?.
Good luck!

quote:

Originally posted by Zeke:
.....

During my last range session, one of my cases had a primer that looked like this



.....ZM

Zeke,

Did the case hit the ground before you retrieved it?

Zeke, I can't help on the primer issue.
But offering big, natural boobs is a hell of a thing to do to a person.

Talk about bait and switch.

Now that you got some help.....Can I see the Boobs now??????????????????

I probably look better without big, natural boobs, anyway.

quote:

The only thing I can think of that may have caused that is maybe there was a small foreign object between the case and the bolt face, and the firing pin struck that object.

Or something close to that.....