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

Who says the copper isn't fouling???There's a ton of products on the market to clean copper out of bbls...

I'm of the opinionthat rough bbls are the real problem... They will lead and they will leave copper in the bbl too... A smooth bbl is a lot more forgiving on both accounts.

Much of the hardeness of lead bullets is surface hardness, and with copper in the same hardness all the way through...

DM

I guess maybe I'm not asking the right answer for the question in mind .

how hard is copper , how come it don't gubber up the bbl till you can scrape out chunks after a 20 round set ina hot bbl

Comparitively a 150 gr flat base triple shok (for illisratation only)is very much like my gas checked 148-155 gr cast bullet ...........
simalar bearing surface copper facing combustion and the cast as I'm led to believe is "slicker"(lacking a better term at the moment) meaning that it operates at a lower pressure to get to X speed .

To site the case , a single shot 45 Colts/410.
I shot some 255 el cheapo cowboys $17 a box they wandered down range and landed in a circle on the paper (8.5x11)and allow me to beat up on 5 gallon buckets to 40-50 yrds (I don't shoot this $50 wonder much) . this gun has 5 very wide lands w pencil line grooves . The copper plated bullets I don't think get any spin in this bbl . The soft cowboy bullet seems to for kicks (and a friend with a ML) I poured some pure bullets that shot well enough to make me almost take the lil'single seriously it would actually keep all the shots at 25 off hand in the circle of black on the OUTTERS 100 yrd small bore target.and show bore lines the platted bullets did not but were impact deformed almost the same as my cast pures.

The lead fouling comes from the gases going past the bullet and a slight amout of melting occures. Lead,as you know,will melt at a lower temp,than copper.
As far as i can recall,jacketed bullets do not all have the same thickness of jackets ! Low speed bullets,such as ones for a hand gun or low speed rifle[30-30 ect] are thinner than, say,for a 30-06 or 7mm mag[hunting bullets].
There is more to it,but,i must go to work.