Originally Posted By ricochet7:
I believe ARP offers polygonol barrels - 16" barrel listed as : ––1 in 8 " twist 5R rifling- .700" UTG, .750 GB, .700 muzzle
Is this what you mean? The 5R I believe is.
I don't think that this is polygonal.
5R is more closely related to conventional rifling.
Polygonal is a different animal.
Black Hole and Noveske use it.