I just moved this weekend and the previous owner of the house left behind what looks like a belt with lead weights attached. Like a scuba diver would wear. It looks very old and I think the weights are lead. Would that be suitable for bullet making ?

As a bullet caster and a SCUBA diver, I ask the following questions...

Do the weights look like a commercial SCUBA product, or "home made cast weights"?

If they look store bought then do some research on what they might be made of.

If home made I would guess wheel weights.

I had some store bought weights, and as a bullet caster I bought a weight belt mold and cast my own out of Linotype.

Sorry but I do not know what alloy store bought belt weights were cast of.

The weights look like a commercial procduct. I have been busy unpacking. When I get caught up i'll take a closer look. They are mounted on a heavy duty nylon belt.
Thanks for you input.

If you can cut the lead with your thumb nail you can shoot it !

My guess would be that scuba weights would be pretty close to pure lead. I also have some that were given to me by a scuba diver.

An easy (and un-scienific) test would be to scratch your scuba weight with a screwdriver. Then scratch a wheel weight with the same screwdriver with the same pressure and effort.

If the scratch is deeper on the scuba weight, then it is softer, and it probably does not have the tin and/or antimony alloys that wheel weights have.

We have used scuba weights for bullets in the past.

Worked great.