A few years back, a couple of shooters scored some really hot 3-groove Harts. I think one of the shooters that had some really good ones was Smiley Hemsley. Everybody got all excited, but I think in the end, those barrels just happenned to be a 'hot lot', that just happenned to be made with 3-grooves.
I would amagine that the record will show that percentage wise, there are about as many great 3- grooves as there are 6-grooves, and visa-versa.
The same can be said for any of our fine custom barrel manufacturers. We have had polygonal grooves, cupped rifling, lands deeper on one side than the other, 3-grooves, 4-grooves, 5-grooves, six grooves, and even the Shilen 8-groove.
All configurations have produced winners, and all configurations have produced, well, not winners.
In short, for 100-200 yard Benchrest, it just doesn't seem to make much difference. A great barrel is just that. Great. And an average barrel is just that as well.......jackie