Good advice. I've had excellent results with three .30-30s and a .44 Mag. with Micro-Groove barrels. Hardness of alloy (between 12 and 15 BHN) didn't have much affect. .30's were sized .310" and velocity ran over 1900 fps while the .44 at .332" ran a little over 1500 fps.

Shew me thy ways, O LORD: teach me thy paths.
"there are few better cartridges on Earth than the 7 x 57mm Mauser"
"the .30 Springfield is light, accurate, penetrating, and has surprising stopping power"