Lest us forget, LEAD is a toxic poison.
Its highly toxic and poisonous should not be used in any way that is liable to be ingested by the body. This includes the use of "fishing sinkers" or any other lead materials to create ball gags, butt plugs, or bit gags.
http://www.nlm.nih.gov/medlineplus/ency/article/002473.htm
Still not sure? Ask yourself why bullets are made of lead? Its cheap, nasty and poisonous, so if the gunshot doesnt kill you the lead poisoning most probably will.
Quoted from CDINBONDS:
"Just handling lead can be dangerous. It is recommended that hands be washed immediately following any contact with lead. Also, lead exposed to water (or saliva) leaches toxins into the water. That is why lead based solder has been banned from use in water systems in the US. Lead based paint is no longer available either because it has been shown to cause brain damage if ingested."