Airgun pellets are suitable lead for alloying
I have sold many hundreds of lead hardness testers and have had customers that used lead from airgun ranges. With the Saeco tester they can use any kind of lead because they know the hardness they want for their bullets and with a tester they can identify the hardness of any kind of lead appearing material and what to mix together soft or hard for their hardness choice.
Tire weights have varied between 5 to 6.5 on a scale of 0 for pure lead and 10 for linotype. For my commercial bulletmaking and reloaded ammo I preferred a consistent hardness of 7 using scrap, tire weights, linotype and tin for my 6,000 pound capacity smelter.