Re: Poor quality chamber-rifling in new rifle. What to do?
My Model 70 Laredo in 300 Win Mag has this problem. I didn't pay much attention in the beginning since the rifle shoot 1/2 minute all day long but, the off center primer indentation always bother me. The right lug, it seems, weren't contacting the recess in the action when the bolt is close. It took several hundred rounds before I finally noticed wear in the right lug signifying contact with the action recess. The other day, while cleaning the bolt, I noticed excessive wear in the right corner of the bolt, just in front of the right lug. Looking inside the breach face, I also noticed a semi-circular gouge, about 3/4" long, at the cone end of the barrel. I believed this is the reason why the firing pen strike the primer off center. It also explain why there is very little contact between the right lug and the action recess. Other than that, the rifle shoot, so I'll leave it alone.
To achieve the maximum possible accuracy, all variables must be remove or at least minimize.