The bore diameter is the important measurement, as 9.3x57 indicated. IF the bore is indeed, .303", then the .315" groove diameter is not the cause of the rifle's innacuracy - something else is.

I've a friend with a #1, which shot 2 groups - ie: it double grouped splitting almost every shot into one group or the other- 1 1/2" to 2" apart and poor groups at that. Bedding did not help.

The rifle double grouped with factory ammo as well as all normal handloads. After he tested a specific powder that I'd been using and raised his speeds to over 3,500fps, the double grouping disappeared and that inaccurate #1 turned into his long range gopher gun - quite a reversal for what today is basically an inaccurate design - in comparrison to bolt guns, that is.

I realize you want to use facory ammo and I cannot blame you for that - your choice. Being that the rifle's accuracy is not as good as you'd like, your only recourse is to attempt to return it and hope Ruger accepts your claims - as you have done.

I susecpt they'll have a representitive shoot the rifle to determine what accuracy it does produce and decide from that to do nothing, repair or replace the rifle.