okay.....I am going against the grain and had my barrel set back after just over 2000 rounds, fresh chamber was cut with a 0.274 no turn neck, loaded Russian brass gives me roughly 3 thou clearance.
fireforming load gave me less then stellar results, but I am pushing 68 grain Barts....and from my experience they like it hot...couple more grains then the Berger bullets and fire forming I couldn't get over 26.5 grains of N133 in the case...
So after fireforming and doing load development, my old barrel was holding in the 2's with a 10 thou jump, but the shape of the hole was weird...so going to play with bullet seating depth and add a tenth of powder.....
3 groove 14 twist benchmark barrel......damn thing is a shooter no matter what the neck diameter of the case.......