Lead bar heavier and less space taken up and don't rust.
Ned
Yes, lead by choice if you can afford it and have access to it; but at least part of the discussion has been about the prohibitive cost of lead, for some people. Hence the discussion about steel, and associated issues with using steel, started by others.
If you have access to lead, lucky you. The last time I got lead, I had to go to a gold mine for an ingot, but not everyone can do that. The only alternative for me, in China, was the fishing tackle shop and buying weights to melt down; which would have been hideously expensive.