[Binkus]

After talking to some friends about the possabilty of HK making a 1911 I got to thinking of how a fluted chamber affects the casings and if they would still be safe for reloading after use in a fluted chamber. Thanks for any imput.

[Gunner45]

My brother got to shoot about 500 rounds through a HK UMP45. He scooped up the brass and gave it to me, and it doesn't apear that the UMP has a flutted chamber. The MP5 that they were shooting was kicking out brass with the tell tale marks on the them, But not the UMP.


Maybe the HK 1911 wont have fluttes either.

Gunner45

[ClarkEMyers]

Some you can and some you can't and some you don't want to.

[QuarterBoreGunner]

Since the UMP uses a gas/piston system for operation it does not require a fluted chamber.

The MP family and the larger H&K rifles utilize a roller delayed blowback system; the fluting in the chamber reduces extraction friction.

I've heard (and we all know how that goes...) that the fluting produces marginal stress lines in the fired brass rendering it unsuitable for reloading. No idea if its true or not.

[SDC]

I've TRIED to reload .308 Win brass that was fired in a fluted G3/HK 91, but it didn't work out too well; the brass extruded too far into the flutes to be sized back down again. :(

[Zak Smith]

I have reloaded many 9mm cases which had been fired in an HK P7. The dark black lines on the case are just powder fouling; the external dimensions don't seem any different.

-z