Any Idea How These Marks Were Caused on the Casings?

My reloading buddy picked these up at the range and neither of us has any idea how the marks were caused. They're nickel R-P 9mm casings. No idea what they were fired from. The marks are around the entire case, but only about half the case has the darker visible ones (the right ones display that). The remainder of the markings on each case can be felt, but are more like a faint scratch (the left ones display that). My friend says the dark marks do clean off if polished by hand. He cleaned up a few, loaded them, and said they worked fine.


http://www.thehighroad.org/attachment.php?attachmentid=179603&d=1360624994


This is my first time trying to display a photo in the body of the post, so here's hoping. Thanks for any opinions.

looks like a fluted chamber (the long, black marks that start at the case mouth and wipe off, that is)

the small little "tick marks" all the way around the case are a crimp to prevent bullet setback

Fluted chamber like in an HK MP5 sub-gun or other blow-back HK pistol.

Clean'm, Choot'm.

It won't hurt a thing.
Except your delicate sensitivities as to how your reloads "should" look.

rc

Probably from an H&K P-7.

Hope this helps.

Fred

Wow. That these fellows can ID the gun you're shooting by the marks seen in an in-line pic is simply amazing. What a forum we have here, eh?

I have a bunch of 308 that have the same marks. Load them and shoot.

Yup, Classic H&K marks (I'd guess from a P7 (http://en.wikipedia.org/wiki/Heckler_%26_Koch_P7))

Looks like the marks of a throw out bearing on a 49 willy's or an H&K

Wow. That these fellows can ID the gun you're shooting by the marks seen in an in-line pic is simply amazing.Aw shucks!

Taint nothing when you been doing this stuff for over half a century. :o

But, I never have ever seen a Willy's throw-up bearing!
Let alone one that looks like a fluted chamber case.

Different life experiences I guess.

rc

Does the headstamp say "Remington"? Some of their cases have that mark on them.

Remington cases may very well have bullet base cannulures on them to prevent bullet set-back during feeding.

But they do not ever have striations on them like the ones in the photo unless they have been fired in a fluted chamber.

Like those most often found in HK fluted-chamber firearms.

rc

Maybe the brass was over crimped, thus allowing it to chamber past the throat, beyond the point where the case mouth head spaces and seals in the throat. This could allow the gases to blow back off of the groves and over the unsealed case mouth.

GS

Maybe the brass was over crimped, thus allowing it to chamber past the throat, beyond the point where the case mouth head spaces and seals in the throat. This could allow the gases to blow back off of the groves and over the unsealed case mouth.

Or it could just be that they were fired in a fluted chamber, like they were. If the case slipped that far forward the firing pin wouldnt hit the primer.

Good grief!

Has no one else ever seen brass out of a fluted HK chamber before??

You can measure those flute marks with a caliper on my computer screen and see they are exactly, evenly spaced on each case, and not accidental marks left by too much crimp.

rc

Good grief!

Has no one else ever seen brass out of a fluted HK chamber before??

You can measure those flute marks with a caliper on my computer screen and see they are exactly, evenly spaced on each case, and not accidental marks left by too much crimp.

rc

I think he was inplying the marks were caused by the riflling grooves funneling the gases back.


To me its obvious its a fluted chamber. :D

Fantastic feedback....what a brain-trust this place is, to be able to even narrow it down to the brand of firearm. Another mystery solved. And no, I've never seen brass from a fluted chamber...they don't let me out all that much.

The cases don't show Remington, just the "R P"

Thanks very much to all. I'll be passing on this info to my friend tomorrow. He'll be glad to get it since he has over 1500 of these.

Definitely out of an HK. My P7 has been spitting those out for years now.

As usual, RC has it pegged. Marks are from a fluted chamber.

Overcrimped? Somebody is over-thinking an already solved mystery, if there was one to begin with? Only a half dozen or so correct answers as opposed to wild guesses. Heckler & Koch pistol or sub gun. I will not say P-7 squeeze-cocker for sure as it could be from a MP-5. Think they may have another variant or so floating around in 9mm with flutes, eh?

Opps, I didn't read ya all's posts before opening my mouth and inserting my foot, ankle, thigh, torso. This is an area in which I have little knowledge, regarding fluted chambers that is. I was actually wondering myself how the FP could even reach if head space was that bad from an over crimp.
And yes, I've never seen the marks left from fluted chambers, until now that is.
Thanks for the heads up on this one guys!
GS

The fact that the OP's pal has picked up 1500 cases indicates that they were fired in a subgun. 1500 rounds fored from a P7 (or a dozen P7s) would result in a firearm (or firearms) hot enough to light a cigar on! :D

definately from a fluted chamber....

if you see the same marks on a .308 case, they were fired in a CETME.

fluted chambers are used on delayed blowback actions, to releave the extraction problems inherent to that design.

Wow. That these fellows can ID the gun you're shooting by the marks seen in an in-line pic is simply amazing. What a forum we have here, eh?

In my best Wisconsinese:

Ya, hey inso? You betcha.

In my best Wisconsinese:

Ya, hey inso? You betcha.
sorry Hondo. but you don't live far enugh north to sound like that ,, LOL but-hey-dare nice try ,

love the 8th post .. but the marks on a 49 Willy's throw out bearing would be from the splined shaft it rides on ,, so.. yep an H&K is all thats left ,( just a guess !!)

I go with ZeSpectre : H&K P7's fluted chamber marks
The brass should be OK to reload, though.