Hi Aladin, It appears this is nothing more than a "near" Pure Lead Mix, with just a bit of Tin from the W/W that aids in the pouring. It is truly amazing what that "tiny-bit" of Tin does in the final formation of the bullet. It might be said that Tin determines the correctness, or fit, of the pour to the mold.....good stuff, indeed! It's very unfortunate for us casters that it is so pricey.Glenn your alloy is in the area of 6.5 BHN--- 8 units of lead [5 bhn ea] and 2 units of ww alloy [24 figuring an aged hardness of 12 bhn] as cast [64 divided by the 10 units]. Thing is-- your compressing that alloy 6 thou which I'd think has to help some. Tin/lead alloys also age SOFTEN to some degree-- ww alloys age HARDEN if their as cast.