Long ago my cousin and I would "mine" the local high school's rifle range (yes, we had one and could bring our own rifles to school - less the firing pin or bolt) for lead from the .22 bullets. We had an NRA (back before NRA became political and angry) marksmanship program for "activity period" and used .22 Longs. On a good Saturday, we could dig 10 to 20 pounds out of the hillside. The only rule was to put the dirt back and pick out any stones that might cause a ricochet. (Other people used the firing range on weekends and non-school days, too.)
We would melt the lead in clean steel cans and cast it into fishing weights in a mold. Caught hell from my grandmother one time when my cousin's can split and lead split on her kitchen stove.