So I finally got around to slugging my Mosin barrels...

And the numbers are .3135 and .305 for the M44 and .312(might even be .311) and .300 for the M91/30.

This explains why the M44 shoots around corners and the M91/30 is pretty close to a tack driver.

I'm shooting cast through the 91/30 because I want to extend the barrel life. Been shooting surplus through the M44 since it was shot out anyway (sewer pipe grooves, rounded lands, still has definable rifling though).

Looks like I need a new mold for the M44.