[ccw1911]

I really think the advantage of the polygonal barrel is lower cost compared to rifling when the manufactor is using hammer forging anyway. In other words I don't think polygonal " rifling" offers anything over traditional rifling. Competition shooters who use Glocks usually go to an aftermarket rifled barrel for increased accuracy and the ability to use lead bullets if wanted. Maybe the polygonal system might last longer when abused in a machine gun but how would you tell it's worn out?

Ross