I've been thinking about casting zinc bullets for a long time now and today I finally did it.
125gr ideal mold and straight zinc wheel weight.
End product ended up being 75gr and sized to .356.
Originally I thought I would try it in 9mm first and then go to 38 special and finally end at 357 magnum. I decided not to waste any time and shoot straight for the moon and go with the torture test of an undersized bullet in a high velocity pistol round.
I loaded it to one grain below max of a 125 gr jacketed bullet with Titegroup. Loaded up six round and shot them into a pine stump, not checking for accuracy just yet, as of now it was just a safety/fouling test of the first six rounds.
I was actually quite impressed with the zinc bullets, nice round holes and stacked together at about 15 feet. As of now I'm very pleased with zinc. That could all change 100 rounds down the pipe!
Now for the down side.
I was using a spare lee ten pound bottom pour pot I had to melt the zinc. I soon discovered that the pot heats up enough to melt the zinc but not enough to pour the zinc out of the spout! No worries I used a dipper to ladle cast.
Second problem I had was mold getting pretty hot, I don't know how good it is to get a iron mold up to 750 degrees or so and then banging the sprue plate. Finally the force needed to bang off the sprue wasn't excessive but I couldn't cut it with my gloved hand, I used a good wack from a large screw driver handle.
So in conclusion, I would say casting with zinc is very possible but, one would need a pot that can heat up to 900° and have enough head pressure to properly fill the mold.