Since I started dabbling with 39A's and trying to learn as much as I can, one thing I've learned is that some are more accurate than others, and there is no conclusive evidence that either microgroove or traditonal Ballard rifled .22 barrels are more accurate than the other.
Sounds like you are fortunate in having a good one.
Paul
I agree. I've found Marlin microgroove barrels no more accurate on average than other rifles within the same price range. They're normally less accurate than many higher dollar rifles, but I'd expect that considering the price difference.
