Strange brass, what's going on here?

[Texas10]

Picked up some really strange looking 308 brass at the range the other day. Any idea what in Sam Hill this is?

[LHitchcox]

Probably regular brass fired in an old H&K with a chamber with those kind of groves supposedly to help with extraction.

[darkker]

Pretty sure the FAL's also ran some scalloped chambers...
But yes, +1 to the above

[Twinsen]

There aren't many designs with fluted chambers, but the CETME and HK ones outnumber the rest 100 to 1 or better. Probably somebody with a PTR-91, Century Arms parts gun, or an HK-91.

Pretty sure the FAL's also ran some scalloped chambers...
But yes, +1 to the above

No, they did not.

The inferior engineering of the roller delay system results in unacceptable bolt velocity, requiring a fluted chamber to prevent case separation. FALs are just gas guns.

[Robinhood]

Yep

[Texas10]

Thanks, mystery solved. For anyone interested, here is a link. Even talks about the fluted chamber.
http://notpurfect.com/main/hk91.htm

[roscoe69]

I have a HK91 and had read once ,that the fluted chamber is to provide a positive extraction by lubing the case with hot gas. mine extracts and tosses the case about twenty feet ahead and to the right, you can walk over and pick it up but it will probably be to hot to hold.

[darkker]

Thanks for the correction

[Balljoint]

But is it re loadable

[Twinsen]

But is it re loadable

If it is boxed primed, yes. But it is oversized and worked a lot so the life of the case is lessened.

The only calibers I've seen with flute marks are 9mm (MP5), 10mm (downloaded for MP10), 223 (HK33), 308 (HK91), 7.62x39 (PTR), and 7.62x54R (SVT40).

The Russian calibers don't matter because they're usually steel. But the 308 and 10mm cases are heartbreaking.

[GaCop]

I have a HK91 and had read once ,that the fluted chamber is to provide a positive extraction by lubing the case with hot gas. mine extracts and tosses the case about twenty feet ahead and to the right, you can walk over and pick it up but it will probably be to hot to hold.

+1, the HK series and Spanish Cetme use a roller lock mechanism that would pull head off fired cases were it not for the cushion of gas the case rides on in the striated chamber. Heavier military brass is recommended for use in these rifles.

[roscoe69]

I had some old IVI brass that I had loaded, probably five times or more but mild, and they got uglier and uglier with each reloading.

[orcldba]

But is it re loadable

I used to get 2, sometimes 3 loads out of HK91 brass. Military brass usually 3, commercial brass usually 2.

Case necks split pretty badly and the shoulders get real ugly real fast.