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 scores decline, often because they did not change their technique or bowling balls appropriately. Some argue that such high technology unfairly affects competition, making high scores too dependent on how much money one spends on equipment. The USBC, for various reasons, has struggled to regulate these changes well enough to protect the integrity of their honor score award program. The problem mostly stemmed from the feature of modern oil patterns, especially house patterns that help exhibit performance of modern bowling balls allegedly for marketing reasons. Every such pattern provides better odds to bowlers with certain line of bowling, release, ball