Duckpin bowling Duckpin bowling Duckpin bowling is a variation of 10-pin bowling. The balls used in duckpin bowling are in (12 cm) to 5 in (12.7 cm) in diameter (which is slightly larger than a softball), weigh 3 lb 6 oz (1.5 kg) to 3 lb 12 oz (1.7 kg) each, and lack finger holes. They are thus significantly smaller than those used in ten-pin bowling but are slightly larger and heavier than those used in candlepin bowling. The pins, while arranged in a triangular fashion identical to that used in ten-pin bowling, are shorter, smaller, and lighter than their ten-pin equivalents,
Ten-pin bowling if synthetic. The top of the pin shall have a uniform arc with a radius of . The USBC also has regulations governing the weight distribution of the pin from top-to-bottom. Pins are allowed one or two "voids" (holes) in the belly area (which can be viewed if the pin is cut in half from top-to-bottom). The voids are needed to balance the narrower top half of the pin with the wider bottom half. Without them, the pins would be too bottom-heavy to fall properly when struck. In addition, a standard regulation pin may lean no more than 10 degrees