I agree with jhalcott on this one. Both brass and lead are easily malleable,(soft). When the pressure of the powder is building, the brass swell out, and the bullet obturate's,squish's out, to ''grab'' the lands and groove's. What will mess up accuracy more with a cast bullet, is if the base of the bullet has a defect in it. I cast my own, but have heard nothing but good on the beartooth bullets, so you should be good there. gypsyman