This weight totals around .0014 per unit of lead...
However, Taking the 9mm round in game, which has a recipe asking for 13 units of lead.
The real world weight of the lead in a 9x19mm round (the round the 9mm in game round is based off) is 7.25 grams, or about .015625 lbs
Divided by those 13 units means each Unit of lead should weigh about 0.001202
Real Weight = .001202 aprox.
Game Weight = .001399 aprox.
Now you may be saying, "So what, most in game weight are off anyway"
And I agree, that's what makes this so disturbing, why is it that lead is so close to it's real world weight equivalent, but we have cups and coffee mugs weighing in at 1lbs each.
Again you could argue that the unit of measurement is not Pounds, but do to the closeness of the real world weight and game world weight of lead, that seams unlikely.
So, ask yourself this, Why is lead so exact and everything else so haphazardly weighted?