Real ballistic gelatin is very expensive, but when I wanted some I spoke to someone at Knox (who is one of the makers of the real thing) and was told that regular, unflavored Knox gelatin like you buy in the grocery store is pretty much the same without the strict controls on quality and ingredients that the ballistics gel gets. I bought about $30 of unflavored Knox gelatin, mixed it up carefully (one of the secrets of repeatablility is to mix exactly according to the instructions every time and keep it at an exact temperature) and poured it into cheap bread pans to harden. Put it in an ice chest and took it out to the desert. For a non scientific test I think it worked great, it gave me a very good idea of the differences in expansion, depth of penetration and permanent wound cavity size between different loads.