I have several 3 groove PacNor barrels in both 17 and 20 caliber, and they have all been excellent shooters, and they clean up extremely easily.
I generally don't spare the powder in those two calibers,and I have never had any problems with bullets coming apart as a result of the barrels.
Also, IIRC, 3 groove is all PacNor makes in their 20 caliber barrels. And I have never heard anyone complain about a PacNor 20 barrel in any way.
JMO - BCB
