Core Hardness

[Duhawki]

Anybody ever check core hardness on a jacketed bullet? I just did for 44 cal Hornady 265 grain FP. I was surprised to find it was all the way down to 4 BHN. To be fair, this is not quite true Brinell. I made the indentation at 30 Kg with a 1/4 inch ball and measured it with reticle in a binocular microscope.
Regards,
Duhawki

[richbug]

Since pure lead runs BHN of 5, I suspect you need to modify your test procedure slightly. Or I suppose it is possible the core was made of Jello.

[runfiverun]

quite often jacketed bullets do have a pure lead core.
other times it's 3 or even 5% antimonial content.
hornady's swaged boolits are 5% antimony no tin.

[Duhawki]

The BH number I reported seemed too low for a reason. No the core was not Jello. It's not even pure lead. (I confirmed antimony content with XRF.) It happened because of a mix-up in samples with some run at a higher load. I re-ran samples and also double checked impression diameters with a Zeiss Stemi equipped with an image analysis system. Finally, I re-verified my Rockwell tester for load. This time the Brinell hardness measures 6. It's still a little lower than I expected, but I believe it is correct.
Regards,
Duhawki

[fredj338]

Most lead cores are running closer to pure than harder alloy. They use the jackete to control expansion & the core for wt. There is little gained, at least in handgun bullets, by using a harder than pure lead core.

[lwknight]

Some rifle bullets have a gradient hardnes like "Core Loct" and "Hot Core" to control expansion.
My remingtom and winchester pistol bullets are pure soft lead core.