Interesting article I did not know that Mercury was ever used to temper lead for bullets. I do know that it is mercury works well to remove leading from barrels. 
  Also it is well to remember that “Mad as a hatter” comes from hatters steaming felt that had been worked with mercury. As they steamed the felt to shape it they inhaled copious quantities of mercury vapor. Mercury goes gaseous quite easily and casting lead alloyed with mercury will surely give off enough mercury vapors to have an adverse effect quite quickly. They practically recommend that you call a hasmat team when you break one of those useless little pigtail light bulbs.

40 Rod