jacketed cores pure ??

[turtlezx]

what the composition of jacketed bullet cores?

[bmortell]

I think sierra labels some of their more "magnum" cores at 4% sb, im about 99% sure I heard that somewhere before. but most stuff is probably close

[Winger Ed.]

If not pure lead, they'd have to be pretty close to go through the stamping/extrusion process smoothly.
And as easy as any protruding core gets dinged up-- its real soft.

The Hornady book has a article and pictures of lead wire going through their factory.
The call it 'lead wire', and then go into a bit of detail about the 'guilding metal' for their jackets-
rather than just calling them copper.

[higgins]

I separate bullet types before smelting. The core metal from jacketed pistol bullets, mostly FMJ, seems to be almost pure lead. I don't have a hardness tester, but it can be easily scratched by the thumbnail test. It was too soft for my use in 800-850 fps .45 Colt loads. It leaded badly after just a few rounds, where the same bullet cast of wheel weight metal was good.

[tomme boy]

4-6% sb from what I recall. None of them are pure.

[turtlezx]

surpizing how soft they seem for 4 to 6sb
friend does his own and buys lead wire @ 1% sb

[tomme boy]

It helps the lead flow and form better. If anything else is added it will get hard fast. But not with Sb alone.