Went in like a stock barrel! Not real sure on the common wisdom but it's seems logical that the micro grooves would not lead as bad or quickly. Other than that I'm not real sure. This is my first .22 target build.Looks like it's coming together. Was the barrel an interference fit, or did it slide in like stock Ruger barrels and some aftermarket ones? When I fit my Kidd barrel into the Kidd receiver it was extremely tight requiring some heat to the receiver and cold to the barrel along with anti seize, and I still need to rubber mallet it in. I don't think it will ever come out. As far as the micro grove rifling, my 39A has that and it shoots pretty well, but what is the common wisdom on that type of rifling on target grade barrels?