In a parallel universe called the real world there is plenty of evidence that lead in any for is harmful to living organisms. This is very well understood by the scientific and medical communities with plenty of supporting evidence. For years dangers of lead have been well understood by military and range operators - especially in indoor ranges. Indeed any packet of ammunition will contain warnings about the dangers of lead.
There has also been plenty of evidence put forward that demonstrates that lead is harmful to wild life, whether this ingested pellets picked up as grit or if eaten as lead fragments eaten as part remains or deer or birds that have been shot.
Indeed the shooting community, through the likes of GWCT, BASC have supported these real world findings.
What the pro lead groups have not done is produce the empirical scientific evidence to support that lead is NOT harmful to living organisms, that ingested lead is NOT absorbed into the blood and deposited into bones etc. They have plenty of time to produce such evidence but so far have not been able to do so. Or if they have submitted to the powers that be, it has been disregarded.
Below is the GWCT advisory note on lead that has been their position for a number of years.
www.gwct.org.uk
However within the likes of the SD community there is a belief that lead is perfectly fine to use. You need to produce the evidence that lead is not harmful to man, bird, beast or plant and you need to produce it in a manner which we will be understood by the Scientific and medical communities and will overturn their widely held opinion, so we can all go back to use lead piping, lead based solders, lead paints and putties, lead in petrol, and lead in cosmetics and on whigs.