Rock's site is www.rockcreekbarrels.com.
He uses the 5R cut rifling taught to him by Boots Obermeyer. His barrels are pretty much identical to Boots.
Honestly the most consistently accurate barrels I have seen. He's not real well known because he is a one man shop, but he did hold the Army contract for the M24 sniper rifles. Pindell of the 6 PPC, uses Mike's barrels.
To be sure, Mike's a nut, but he makes a damn good barrel. My ass is on the line everytime I screw one of his tubes on an action, but I trust him.