I'm sure that by now I'm starting to look ..... well never mind .

How hard are copper/guilding metal or pure copper jackets/bullets ?

I've read that a cast lead bullet is "functional" to a hardness of 22bhn for general use . Dead soft lead being around 8 ( don't beat me up I don't have the artical in hand) .

I realize that copper, guilding, brass, bronze(?) etc is of totaly differant properties of flex bend expantion and heat resistance .

Why does a very hard (22bhn)lead lubedbullet "foul" at (eg) 2000 fps and or skid the rifling while a very soft "pure" copper bullet does not until perhaps 3500 fps with a similar hardness