Bowling ball random when impacting a full rack of pins on the first delivery of a frame, and sometimes when hitting downed "dead wood" pins on subsequent deliveries—the candlepin bowling sport is the only major one that allows fallen pins, provided no part of any fallen pin extends more than 24 inches (61 cm) forward of the head-pin spot, to remain on the lane's pindeck to be used in knocking down more pins with the next ball delivery in the same round—up to three balls are delivered, much as in duckpins, in each round of candlepins for one bowler. Bowling ball A
Ten-pin bowling determining success in the sport of bowling." The USBC completed data analysis and released a lengthy report on its website (www.bowl.com) to the public in the spring of 2008. As of April 1, 2009, The USBC now regulates the chemical surface roughness of all bowling balls manufactured for certified ten-pin bowling. This specification is a direct result from the ball motion study, as the surface roughness of the coverstock of a bowling ball was the number one variable (out of 18) that affected the strength (how much a ball hooks) of a bowling ball. The radius of gyration specification has