Anyone know what caused this?

[Cerberus Group]

I don't see the deep case striations from an H&K.
Never saw an extractor mark like that, but OK.
Ding on side indicates hitting frame on ejection.
It's the missing primer that really is scary.

I've seen plenty of HKs that leave those longitudinal marks.

MP5s (and all other guns in the same family of roller-delayed blowback firearms suck as HK G3, HK33/53, G41, etc) have fluted chambers to equalize the pressure. This helps keep the case from sticking in the chamber. I.e. the gases inside the bore will run back around the case inside these fluted grooves.


This is necessary as the roller-delayed blowback mechanism starts to cycle much earlier than other typical designs, and without the flutes, the pressure inside the casing would be so high that the casing walls would stick to the chamber walls while the case head is ripped off.

I've seen plenty of missing primers from fired rounds...mostly come from Lake City brass. Some people think Lake City LC brass is great...it's not. The primer pockets are all over the place for spec, and some don't have the tension to hold a primer very well...thus they will blow out upon firing.

 

[Stomper]

I find those quite regularly at "the pit" but never saw no blood or body parts laying around.

Cuz coyotes…..

 

[Caveman Jim]

Cuz coyotes…..

Too funny, was out at the pit the other day and found some sign of critters.

 

[Stomper]

Too funny, was out at the pit the other day and found some sign of critters.

View attachment 1804088 View attachment 1804089 View attachment 1804090

I see that you tried to spell your name in the snow…..

 

[CLT65]

I've often found brass like that too, with HK/CETME style flute marks on the necks, dents and raised over-pressure marks on the base.

It's hard to tell with mangled brass, but much of it looked like factory loads to me. I've wondered if there was something about the design, or maybe lousy manufacturing by a certain company, that made these rifles prone to over-pressure?

 

[Mikej]

I see that you tried to spell your name in the snow…..

Ugh, caveman not spelvery good. Rrr.

 

[noylj]

I've seen plenty of HKs that leave those longitudinal marks.

MP5s (and all other guns in the same family of roller-delayed blowback firearms suck as HK G3, HK33/53, G41, etc) have fluted chambers to equalize the pressure. This helps keep the case from sticking in the chamber. I.e. the gases inside the bore will run back around the case inside these fluted grooves.


This is necessary as the roller-delayed blowback mechanism starts to cycle much earlier than other typical designs, and without the flutes, the pressure inside the casing would be so high that the casing walls would stick to the chamber walls while the case head is ripped off.

I've seen plenty of missing primers from fired rounds...mostly come from Lake City brass. Some people think Lake City LC brass is great...it's not. The primer pockets are all over the place for spec, and some don't have the tension to hold a primer very well...thus they will blow out upon firing.

The H&Ks I've seen leave very deep striations. Must be old eyes, but the outside of the case looks normal, even shiny, to me.

 

[GWS]

The gun was purchased and ironed out (so I'm told) by those who sold me the ammo. I bought a new HK91. $444.

$444?? That must have been a long while ago.

 

[po18guy]

$444?? That must have been a long while ago.

Pure 80s nostalgia rather than 2024 neuralgia.

 

[ageingstudent]

I see that you tried to spell your name in the snow…..

He did better than I could with my "10 lb prostate"... unless I take my flow-max. Then I can spell like an English major

 

[Stomper]

He did better than I could with my "10 lb prostate"... unless I take my flow-max. Then I can spell like an English major

Are you inferring calligraphy?

 

[ageingstudent]

Are you inferring calligraphy?

Something like that

 

[po18guy]

$444?? That must have been a long while ago.

BJB

Before Joe Biden

 

[Benchrest]

Looks like it was fired out of an HK91 type rifle and that it was a hot handload, impressing the case head with the bolt face and blowing out the primer.

Hot seems an understatement

 

[PORSCHE928S4]

Century built rifle.

Homebrew reloads, with God knows what for components.

It gawts da sawltpeeter in it dawg !

 

[PORSCHE928S4]

Were you able to buff that out?

A lil rouge and will buff out no issues at all !