I am not sure that micro-groove barrels are more accurate. I AM sure however that they are cheaper to produce than deeper rifling.

Marlin talked up less bullet deformation with the shallower grooves. But anyone who has ever run an old BRNO or even the new CZ 45Xs knows how accurate deep rifling on a 22 rimfire can be.

Anybody who seriously concerns themselves with the adequacy of a Big 7mm for anything we hunt here short of brown bear, is a dufus. They are mostly making shidt up. Crunch! Nite-nite!

Stolen from an erudite CF member.