Free floating the barrel is simply a matter of sanding that 3 inches of contact to provide clearance. Sandpaper wrapped around a deep socket of sufficient diameter is what I have always used. But, you should be sure you want to free float the barrel before you do it. In my experience free floating the barrel has improved the accuracy of the few rifles I've done this to, but I don't believe free floating is guaranteed to improve the accuracy of a factory hunting or varmint rifle. If the rifle was mine I would not free float the barrel until I had developed loads for the rifle, shot them extensively, and became convinced free floating was the next necessary step to achieve acceptable accuracy for the rifle. On the other hand, free floating can be reversed by glass bedding at the foreend.
NRA Life Member - RMEF Life Member - Vietnam Vet