Overpressure? Pictures inside.

[Nessal]

I went to tumble a bunch of brass today and I do my routine checking before I throw it into the tumbler. Of 150 brass casings, there was two that looked to have pressure issues. There is a groove and bump on the headstamp and what looked to be case head seperation. You can feel the groove where the line appears on the case body. This was all shot out of an AR15. What do you guys think?

WARNING VERY BIG PICTURES!

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[swerv512]

how are you sizing these?? FL?? Small Base??
i see the ejector marks, but i believe that's common on ARs (?)... correct me if i'm wrong...
how are the primer pockets? can you slip a fresh one in the pocket with ease- does it fall out with little effort?
was there signs of gas leaking around the primer before you deprimed the cases??
have you measured the around the case web for expansion???

[CalNative57]

have you tried the bent paperclip to see if you can feel a weak spot in the ring? your pic of the end view looks like its bulging slightly. I agree with swerv512 and would measure it for expansion. Just my .02

[J-cat]

Ejector marks where brass flows into the hole are not common with AR's.

[five.five-six]

what lens are you using? those are nice macro shots

[johnrunner89]

I never seen anything like it.

[swerv512]

Ejector marks where brass flows into the hole are not common with AR's.

thanks for the correction. i have seen cases (M700) where the ejector marks were made by a sharp-edged ejectors that once polished, no longer made the marks. i've seen this twice. however, seeing other signs along with the ejector marks could be cause for concern...

[Linus]

Them extractor marks lead me to think that you do have some pressure issues. I would cut one of those cases lengthwise to make sure there is no case head separation. What are the specs on the reloads? (Powder charge, bullet, primer and # of times the cases have been reloaded) Also, have you checked your rifle for proper headspace?

[Bug Splat]

WOW! Yeah there should not be that much flow in the brass. What are the load details? Powder, amount, primer, bullet type and weight?

[EOD3]

What do I think?

I think it's a "praise Jesus" miracle your rifle isn't scattered all over the range.

Based ONLY on the appearance of the brass, you are WAY over SAAMI pressure limits.

[American_pride]

What do I think?

I think it's a "praise Jesus" miracle your rifle isn't scattered all over the range.

Based ONLY on the appearance of the brass, you are WAY over SAAMI pressure limits.

[Nessal]

how are you sizing these?? FL?? Small Base??
i see the ejector marks, but i believe that's common on ARs (?)... correct me if i'm wrong...
how are the primer pockets? can you slip a fresh one in the pocket with ease- does it fall out with little effort?
was there signs of gas leaking around the primer before you deprimed the cases??
have you measured the around the case web for expansion???

These are full sized. The ejector marks aren't normal I believe. The primer pockets are fine. I primed one of them for the hell and of it and it went in and stayed in. No signs of gas leaking. I haven't measured the case web yet but will do that tomorrow probably.

[Nessal]

what lens are you using? those are nice macro shots

Just a normal point and shoot Canon SD1000. It's a pretty old camera but works great still!

[Nessal]

Them extractor marks lead me to think that you do have some pressure issues. I would cut one of those cases lengthwise to make sure there is no case head separation. What are the specs on the reloads? (Powder charge, bullet, primer and # of times the cases have been reloaded) Also, have you checked your rifle for proper headspace?

I usually shoot a bunch of handle loads in varies grains of bullet. Then check them to make sure that they are ok before they go into the tumbler. So the loads can be either a 75gr load that I've been working on or a 62gr load. These should be twice-third fired brass. The specs of each are....

75gr HPBT
22grn Varget
CCI #41 Primer
medium crimp
Case Length 1.75"
OAL 2.250


62gr FMJ
23grn Varget
CCI #41 Primer
Medium Crimp
Case Length 1.75"
OAL 2.250


It's really weird because none of the other cases have this happen and I was using VERY conservative charges. I loaded thousands of rounds and never had this happen ever. What other possible reasons? Possible that the bullet got pushed in when hitting the feed ramp causing excess pressure? I'm stumped here.

[gregm727]

Yes. Over pressure. Be happy you didn't lose something along the way. Back off to minimum loads and start over.