In 5R® rifling, the barrel has 5 grooves and the sides of these grooves are not straight, (i.e. not parallel to each other), instead they are angled or ramped as shown in the drawing above. Many shooters find this groove style to be advantageous, which has led us to offer it in many of our calibers.
True 5R® rifling is an official registered trademark of Boots Obermeyer of Obermeyer Barrels. Krieger Barrels has express permission to use both his "5R" terminology and the groove geometry he developed to produce our 5R® barrels. Our 5R® barrels are produced using the same methods and standards of match-grade quality as all of our barrels.
There is an additional fee of $30 for 5R® barrels.
Currently, 5R® rifling is only available in the standard twist rates for that caliber unless otherwise noted. We do not offer custom, non-standard twist rates in 5R® at this time. We also do not offer 5R® rifling in our semi-auto barrels. Barrels which require a gasport are always made with 4 grooves so that the grooves are wide enough that we can keep the entire gasport within the groove.