Columbia 300 Bowling Balls. Columbia 300 Bowling's Backyard Bully brings to market the perfect combination of core and coverstock. Columbia 300 combined the proven mallet core of the Bully and Big Bully with the revolutionary M802 coverstock. M802 is the latest leap in coverstock technology from our friends at BASF. You will see a stronger, more angular backend motion. Don't even think of coming into our Backyard!