I have two rifles in the Fireball (SPS Varmint, CDL Ltd edition....SPS is 4 sale) and both are great shooters. As far at the fouling goes I have not experienced anything unusal or heavy. My CDL just went 80 rounds with no degradation in accuracy, and copper was minimal ( 3 patches of Butch Bore Shine....done !!) Just dropped a dog the other day at 227yds with the 20 gr V-Max and it fell like a stone. Couldn't even find the entrance hole....LOVE IT ! My .22-250 has almost taken a back seat to this new caliber.
http://www.varminthunter.org/downloads/Issue62.pdf
http://www.varminthunter.org/downloads/Issue62.pdf