Gentlemen,

How do you harden lead and how fast can you push these hardened projectiles?

Thanks much

Add tin or antimony or drop the bullets in water as they come out of the mold. Or do both.

How fast you can push them depends on how hard you make them. Make them to hard and you can end up with brittle bullets.

Esskay,

Go to the cast boolits site. You will all the information you could possibly want or need. If you can't find what you need on that site it doesn't exist.

http://castboolits.gunloads.com/

Gentlemen,

Thank you very much for the info.

Ah yes the old water trick..apparently it works btw, and it makes good since..

Esskay

It might be better if you mention what your final goal is.
Answers to your original question may be more defined if that final goal is known.
Conical or ball?
What is your lead source?

Just use clip on wheel weights or buy alloy form roto metals if the goal is a harder projie.

Do not think one can harden pure lead much if any at all.