I agree with just using some bore paste on a new rifle to smooth things up some. BUT the Tubb system does have it's merits. I used it on an old rifle I had picked up. This thing copper-fouled horribly due to the rough condition of the bore (due to an apparent history of poor cleaning). Anyway, running all the grits of the Tubb system made a BIG difference in it's fouling problem and with accuracy too.

I really wouldn't hesitate to run a set of rounds of the finest two grits through a new factory bore to smooth things up - but I wouldn't do it to a custom barrel.