August 16, 2004, 12:28 AM
Polygonal rifling seems to be an interesting design, it's used by HK, Glock and Desert Eagle. Is there pro/con to it? My desert eagle barrel looks really nice after each shooting and cleanup is a snap. No residue or jacket fouling stuck in lands/grooves.
August 16, 2004, 12:39 AM
I've heard reports that bullets with very thick jackets can cause higher pressures in polygonal rifling because they do not "reshape" to the flat-sided rifling very well. I've also heard that barrels with polygonal rifling are much more expensive to make because they have to be hammer-forged.
August 16, 2004, 12:47 AM
One reason is that it's dangerous to use lead (and some say copper-washed) bullets in polygonal barrels, as the pressure is vastly increased.
It's all a big trade-off. It would be nice if guns would come with traditional and polygonal barrels fitted to the gun... but what are the chances?
August 16, 2004, 04:19 AM
It would be nice if guns would come with traditional and polygonal barrels fitted to the gun...
Well... if you had an early USP40 like me you could have the traditional barrel. And then you could get a new barrel with polygonal rifling.
I prefer the traditional since I like the option of using lead (or soft jackets) without a problem to worry about.
August 16, 2004, 07:09 AM
Mainly its because most of our reloading data and testing equipment is geared towards conventional rifling (liability lawyers:barf: ) I see no logic that higher pressures result since the bullet bearing surfaces are the same regardless of the type of rifling, what rifling DOESN'T support the bullet walls 100%? The main problem is the build-up of lead residue that can cause problems with proper/safe chambering (Glock) and the gas system (H&K P7-8). Hard cast bullets should work fine but how about the risk factor involved with the guy that shoots 500 rounds of butter soft lead bullets without cleaning his pistol?:what: In traditional rifling, the lands and grooves will "trap" the residue. In polygonal rifling it just builds up on the walls of the bore (like a shotgun) which results in a gradual increase in pressure that continues upward until removed (cleaning) or KA-BOOM!
August 16, 2004, 10:44 AM