Armor Penetration and Armor resistance.

[Dan Howard]

Hmm...weight in Hellenistic period for a General would not be much issue since they were all (or almost all) horsemen riding with their HETAIROI in battle a and could afford big horses.

And a question can a hand-propeled weapon (i.e javelin) attain 30-40J from an average thrower?

Kind regards

2mm of work-hardened bronze could easily withstand 120J from a javelin. This is not enough to stop a modern Olympic javelin even at a fair distance but ancient javelins would have more trouble. However, many cuirasses seem to have been closer to 1mm in thickness. This is enough to stop most arrows but not thrown javelins (single-handed spear thrusts and sword stabs have no chance at all). IMO the growing prevalence of body armour at the end of the bronze age caused the bow to be discarded in favour of javelins.