This week sees two new teams battling to become the fastest golf-ball guns on the scrapheap. The day started badly for the Clean Sweeps. They discovered that their ball-feeding mechanism was jamming and were forced into a last-minute rethink. Unfortunately this turned out to be just the first of their problems. Round one was a test of speed and accuracy, and the Sweeps struggled on both fronts: their aim was wayward and motor problems reduced their rate of fire. The Boat Buoys on the other hand looked the genuine article, delivering a string of balls into the moving target and shooting themselves into the lead in the process. Round two was designed to test the machines' sheer power: the object was to smash a wall of bathroom tiles. The Sweeps were forced to abandon their erratic motor for a cordless drill and, although they made an impact, they were no match for the blazing firepower of the Boat Buoys.