Re: 300 RUM Issues...
I honestly don't remember how far off the lands I am and don't really care, because it shoots very good at magazine length. Last I remember though is that I have a pretty long throat, so getting close to the lands isn't an option.
In regards to the low velocity with the OP rifle, I would take the gun to a smith and have the bore cast and measured. Sounds to me like a tight bore or possibly a rough bore that isn't fully broken in.
Remington model 700 300 RUM LH 26" rem ss/blued receiver lam stock 215 Berger @3070/180 NAB @3300/Leupold 6.5-20x50
Remington model 700 338 RUM LH 26" Bartlein 5C #4 Muscle Brake, blueprinted action, sako extractor, jewell trigger, bell and carlson Alaskan stock/Black cera coat/Sightron SIII 8-32x56 moa reticle, external elevation turret
Savage LH 22-250/Sightron 4-16