I'm using Hornady precast roundballs in .310 and was wondering if they are pure lead?
The balls Hornady sells at .310" for muzzleloading rifles, are about as pure as you will find.
We started using the term dead soft when describing the balls we cast, due to some nit-pickers who said our pure lead, plumbers or roofing flashing wasn't pure as
it contains up to 1 1/2% of other alloys or materials - thus, the 98.6% pure Plumbers lead was not 100% pure.
We lucked in to the lining from the X-ray room at the hospital when they changed rooms. It is more pure than-is plumbers lead as I have to add a bit of tin, 1/2" of 50/50 to 20 pounds,
to prevent excess crusting on top from oxidation.
So - roof flashing - quite pure - dead soft
Sewer roof vents - quite pure - dead soft
E-Ray Wall lead -- quite pure - dead soft
If you drop a 1 lb. ingot of this dead soft lead on the concrete floor, it goes thud & gets a huge dent. IT does not ring. Lead with any appreciable amount of antimony in it, will ring & deny much less. Tin/lead mix is easily see (shiny not dull) to be alloyed. Alloys are very difficult to cut easily with a thumb nail, or pocket knife. You can cut a chunk off a piece of dead soft lead, but almost impossible to do that to a piece of alloyed lead.
Pure lead, ie: plumbers lead has a brinel hardness of 5. Lead clamp or crimp on wheel weights used to be brinel 10 to 13 depending where they came from. Lyman's #2 alloy for shooting lead bullets up to 2,000fps in modern guns has a brinel of 16. Linotype has a brinel of 21/22. Monotype has a brinel of 26 to 28. Dead soft pure copper has a brinel of 35.