BC - you shouldn't need anything more agressive than Shooter's Choice during break-in, after firing only one round through a premium barrel. Maybe a rough factory barrel - with a Barnes X bullet.

One nice thing about Shooter's Choice is that you can leave it in the barrel for awhile with no problems. More agressive cleaners like Sweet's (which I use a lot of) and Barnes CR-10 can ruin a barrel if you leave them in there overnight. So my advice is to use the least agressive cleaning solvent that will work - even if it slows down the process a little.