308 twist rate.

[Liven The Dream]

5R® Rifling Form Just off a little on my info. Sorry for this .
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

 

[284winner]

I Gaurantee your never too old to learn. Im wrong alot. I'm learning i have been wrong quite often. Much more since I started my account right here in this forum. Tim North of Broughton barrels has very fine 5r barrels certainly non out there are superior to his. Many are as good. I've owned Bartlein, Kreiger, Lilja and Benchmark and they are certainly no better but they are as good. There are also many other fine barrels out there that will one day set on one of my actions. Cant say I've had a barrel I didn't like as of yet. There's still time.

 

[Caleb85]

Lets talk freebore? .90 enough for the 168-175?

 

[Ned Ludd]

You can seat a 185 Juggernaut at .015" to .020" off the lands (touching) in a chamber with .085" freebore, but the boattail/bearing surface junction is just barely above the neck/shoulder junction. As you might imagine, the pressure will also run higher than with a more generous freebore (~0.130" to 0.160"). In one of my rifles with .085" freebore and a 30" barrel, I'm pushing the Juggernauts at ~2725 fps (OBT Node 4) with Varget. QL predicts the pressure to be very close to 61K psi. Brass life is reasonable for this load. However, I also worked up a load with 185 Juggernauts and H4895 at 2750 fps in the same rifle (same OBT node) and it was much closer to MAX pressure (62K psi, SAAMI). On a very hot day, that load was a little too hot IMO. So .090" freebore will work with Juggernauts, but it is not optimal. Dave Kiff at PTG makes a reamer with 0.168" freebore specifically designed for the 185 Juggernauts. IMO, that might even be a tick longer than necessary. As mentioned above, somewhere in the 0.130" to 0.160" is where I would go. In addition, .090" is not sufficient to keep the boattail/bearing surface junction above the neck/shoulder junction with 185 Hybrids, which are slightly longer. In contrast, with 0.160" freebore (or 0.168"), you can effectively load up to the 200 Hybrids, lengthwise.