Fred, there are no lead sheets in car batteries, nor have there been since "sealed" batteries, aka wet charged, were introduced. The plates consist of grids enclosed in plastic envelopes and in addition to lead contain cadmium and antimony. That's why batteries must now be recycled. If you were to open a used battery and removed one of them, it would crumble in your hands like a cracker. However, large, dry charged industrial ones still contain lead plates.There are a lot of lead sheets inside a car battery. I had a school in one of the Delco Remy battery plants and got about 10 feet of the lead sheeting rolled up from one of the employees
As for lead water pipe, a friend who was a supervisor for ComEd in Chicago had 1500 lbs collected from job sites and he gave me 500 lbs. It was 6" OD. In areas where they were burying their electric lines, the municipalities would come in and replace their old water lines since they had a common utility easement.
Long range muzzleloader shooters and Civil War musket shooters use a bullet that is around 540 grains so you get 13 bullets per pound. A match can consist of up to 100 shots so you can see that 500 lbs doesn't go far.
If we want to get Carlos started in reloading, I've got milk crates full of dies, presses, brass, and bullets that I haven't used in over 15 years. It'll all probably get sold at my estate sale when I croak.