I have melted several pounds of range scrap in the past, usually while cleaning up some wheel weights and some other softer lead. I wanted to track the weight and yield to see how it actually came out after reading some accounts on this site.
First, it is pretty dirty stuff. Lots of jackets, paper, and fibers from the belting we use at our range to trap bullets. Our range is 50' with a metal backstop. There is everything from whole cast, complete jacketed to lead dust in the mix. I have an old plumbers pot and heat source that works well, not overly big or fast. I sometimes work with a buddy who lives several hours away and he has a turkey cooker that really gets with it. There is a lot of junk on the surface that needs to be cleaned off. I would put three scoops with one of my wife's garden hand digger, put my 6" cast skillet over the top and walk off for a few minutes and do some other work around the house. I did find I had to stir it because the junk would hold solid lead above the molten lead and unless I stirred it, it didn't all get melted in. The debris I removed would probably burn all day if I let it. The interesting part for me was after I cleaned off the waste, the lead was really pretty clean. I assume some of the waste product acted like a flux in some way, I don't know the science. I would flux with small pieces of wax with my stir spoon and my pouring ladle. If I put too much wax in I had a black liquid to chase around the top of the pot so it didn't take much.
I did three different buckets and these are my yields.
95.2 lbs of range lead - 66.4 lbs of lead yield - 70% - 75 ingots with a Lyman mould
64.6 lbs - 46.6 lbs lead - 72% - 48 ingots
87.4 lbs - 62.2 lbs lead - 71% - 63 ingots
So, out of 247 pounds of scrap I drug home, I ended up with 175.2 pounds of lead. I still have 2 1/2 buckets to go once the rain lets up here. I would add that I have no idea what the hardness of this stuff is. I have shot it before and never a problem either with Alox, Alox mix, or PC which I am doing mostly now, but I do not push anything real hard and fast. Is it worth it? If I can spend a day making a mess and stink to come up with 2-300 lbs of lead, it is probably worth it to me. Wheel weights are getting much harder to find in my area. My local scrap dealer will sell lead at $1.00 a lb that I would still need to melt down and work with. I would add that I don't real excited about the beauty of my ingots, if they are a bit wrinkly, that is OK with me, just tells me I am not getting my lead too hot.