I've copper plated bullets using a automobile battery charger, Copper Sulfate (Bluestone Root killer), a square plastic bucket, a BBQ rotisserie motor and shaft, scrap copper wire, and a few pieces of carbon from a battery or starter brushes. You need to rotate the bullets in the plating solution or they grow little wires (dendrites) that make them rough and lumpy. Set up a plastic bucket with a lid on the shaft of the old BBQ rotisserie, using the adjustable prongs to center it and hold it. Pre-drill a few dozen or more holes in the bucket; the more the better. Don't make them bigger than the bullets. I used a bucket that premixed wall board 'mud' came in. The bucket has to be small enough so the motor can rotate it, when it's loaded up with bullets. The bullets go in the bucket, which rotates on the rotisserie shaft, which is supported by a short piece of copper pipe soldered or clamped to the square rotisserie shaft. The copper / shaft rotates on a piece of graphite or starter brush on one side of the bucket, providing a bearing surface and electrical connection to the NEG - MINUS side of the battery charger. The other end of the shaft goes in the rotisserie motor. The solution is distilled water with a handful of copper sulfate ( experiment! ), deep enough to submerge the bullets while it rotates. The other battery cable connection goes to a web of copper wires (scrap wire with the insulation cut off) positioned on the bottom of the square bucket to clear the bucket as it rotates. As the current flows copper will plate onto the rotating bullets and the prongs. Copper from the wires on the bottom will dissolve into the solution to replace what is plated out these are connected to the + POS side of the charger. The wires in the bottom will get thinner as they are eaten away. You can adjust the temperature, the charger setting, the concentration of the solution, and the distance between the wires on the bottom and the bullets. The last time I did it, over 25 years ago, the bullets (.429 SWC straight wheel weights) plated to a red copper color which I couldn't dent with my fingernail, and stayed on the bullet pieces after it went through an old RR tie. The finish is not real shiny, but rather red , hard, and rough. The tumbling in the bucket puts a lot of tiny dents in the surface. After the plating, I washed them real good a few times,dried, then lubrisized them with Alox /Beeswax. As to the toxicity of the solution, it's legal to dump the copper sulfate solution into the sewer, or they wouldn't sell it for that. The solution is reusable, as the copper is replenished by the wires in the bottom. Just pour it into a safe plastic container. Store it away from kids, and wear rubber gloves, as it is poison. There are many things that could improve the plating, and make it look better, but this simple process does work, and is a starting point. If the bullets are lubrisized they should be the correct diameter. You will have to check the weight.
