<Li> Model rocketry: to add weight to the nose of the rocket, increasing the stability factor . </Li> <Li> Due to its relatively high heat capacity and low thermal conductivity at low temperatures, lead shot has been used as a suitable material for a regenerator in Stirling engines and thermoacoustic cryocoolers . </Li> <Li> Due to lead's high density, it is used to attenuate radiation, especially X-rays and gamma rays . Lead shot may be enclosed in a bag and then be placed around a point source for radiation protection or for radiation shielding . </Li> <P> Lead shot - related waterfowl poisonings were first documented in the US in the 1880s; by 1919, the spent lead pellets from waterfowl hunting was positively identified as a major source of deaths of bottom - feeding waterfowl . Once ingested, stomach acids and mechanical action cause the lead to break down and be absorbed into the body and bloodstream, resulting in death . "If a bird swallows only one pellet, it usually survives, although its immune system and fertility are likely to be affected . Even low concentrations of lead have a negative impact on energy storage, which affects the ability to prepare for migration ." Upland game birds such as mourning doves, ring - necked pheasants, wild turkey, northern bobwhite quail and chukars can also ingest lead and thus be poisoned when they feed on seeds . </P>

What type of shotgun pellets are allowed for waterfowl hunting in the u.s. lead