What kind of rilfe did this?

[JPH45]

Sorry no pics, unable to, but I was at a range recently and picked up 40, 308 cases. The neck had lines cut around the neck, looked like rifling in a way but was not. Cases were heavily smoked as if they were being extracted early in the breech unlocking event. Any idea?

[Buford]

HK rifles had a fluted chamber that would cause this.

[Graybeard]

Sounds a little like blanks from your description but without a photo it's hard to tell. Do you know what fired blank cases look like?

[Mikey]

Boss - it sounds like a Heckler and Koch to me.  One thing I noticed when they were first introduced was 'the rifling marks' around the neck and how dirty the cases were.  Manufacturer stated the chamber fluting that caused those marks was to help assure reliability in the field.  Actually, that was one reason I never bought one........Mikey.

[1911crazy]

It sounds like fluted chambers the Spanish 308  Cetme also has a fluted chamber.

[bluebayou]

I found these and asked the same kind of question:



They are from a CETME, but apparently, the HK does the same thing.  HK is based on CETME design and both have fluted chambers for easier extraction.

[corbanzo]

Looks like a blowback problem waiting to happen to me....

[HotGuns]

That is exactly what it is...blowback....

and that is what the rifle is designed to do.

Once the pressure reaches a safe level after firing, it the bolt unlocks and the resulting bit of gas actually aids in extracting the spent case. It is done for reliability in battle conditions when the rifle gets dirty from extended firing.

It works too, my G-3 thows the cases about 25 feet away from the rifle.

The only disadvantage is that the cases look pretty rough after firing. They'll still cleanup after a good tumbling.

[saltydog]

CETME or HK 91 -G3 or clone will leave the flutes. The cases pictured look more like a CETME to me.

[SHOOTALL]

alot of full auto guns have fluted chambers to aid extraction when heat builds up , ammo is dirty etc.

[TNyoteboy]

Lines on the case came from an H&K design. Our MP5s do the same thing to a 9mm case. Cuts on the neck probably come from a blank round where it was crimped closed.

[MSP Ret]

I have heard that quite a few military full autos have this feature to aid in positive extraction/ejection also....<><....