Bren 30-06 barrel with fluted chamber

[RASelkirk]

You've never seen anything coming out of an HK 33 or 91 or 93? Or a G3? They all have fluted chambers too, the MP5 should have too. They all allow positive extraction but are very hard on brass. They weren't meant to supply reloaders with brass.

No, I didn't even know this type of chamber existed. What would be the purpose? Obviously, the mfg'ing expense would be much higher so I must assume some type of benefit...

Russ