Good ideas Light'in......unfortunately re-loaders and some others have had the same idea
In order to get the lead they need they have arranged with local tire shops to purchase all their scrap lead. Seems everybody using "old" lead is in the same fix.
What I decided to do...out of expedience and unbridled curiosity is the make the ballast bulbs for my Footy and Pea Pod using resin/BB's. Wanted to see if the BBs would serve and what drawbacks resulted. What I found was, they served well....but resulted in a somewhat larger bulb. Guess that's to be expected. Unfortunatly I haven't been able to locate bird shot for a heads-up comparison between the mass that lead presents vs. steel. Just guessing...maybe twenty percent larger steel bulb. The other drawback is that it's near impossible to reduce or change the shape/size of the bulb made with BB's. That's to say, grinding the bulb produces BB's recocheing around the shop at the speed of light. NOT a good result.
So, about the only safe way to alter the shape/weight of a resin/BB casing is to INCREASE with a filler such as Bondo. In the future, I think I'll first lay up a skin of glass cloth/resin in my plaster mold then fill to correct weight with BB/resin....leaving a void to allow for more BB's as needed for fine tuning. But, I reckon the cost/labor of using BB's to amount to nearly the same as lead. The main difference being in mass/availabilty of material. Two things are for sure though....probably...... the situation with disappearing lead supplies is only going to get worse, until......
and the joy of modeling is experimentation.