The fluted chambers in HK rifles are put there to aid in positive extraction. Makes the extracted cases look very strange but do not seem to affect reloading of the brass although the case life must be shortended a bit. They are straight flutes. I believe you are correct Bill in stating that the spiral flutes in the rifle in question were probably caused by a chattering reamer.

I believe Mr. Leeper is right. I don't see how else it could happen. Jim

I'll try to get a picture posted, it really lookes exactly like what you see when you look down the barrel. Striations evenly spaced with a very slight twist. Sorry for the contreversy...

captainkirk

Ray,
I'll agree the win's are springy...

but not the 99....

jeffe

Is a fluted chamber a possibility? I`ve never heard of one that had a twist but I`ve heard of cases that had marks on the body supposedly from fluting. I believe the cartridge was a military round fired in a military weapon though, not a commercial job.