Help ID this alloy

[PanaDP]

Hey, everyone. I went to pick up a bunch of pure lead from a guy today and he also had these blocks totaling about 35lbs, I estimate. Each one is 2" thick and 5" each tall and wide. One edge is flat but the other three are a vee shape so the blocks can fit together.





I don't think it's pure, it's too shiny and it has a bit of a ring rather than a dead thud when dropped. It is pretty soft, though. I hit one with a hammer alongside a piece of pure certified lead, taking care to try and hit them with the same oomph, and the dents were almost identical.

Any idea what these are and what alloy they are?

[letsmeltlead2693]

Looks like something used for radiation shielding.

[runfiverun]

or race car rails.
they are holding a shine, if it's malleable and you can't break a thin edge it's softer than ww's.
i'd try to break one of the v's,if it takes some work but eventually breaks instead of smearing i'd call it ww stuff.

[AndyC]

Check this out: http://www.radiationproducts.com/bricks.htm

[PanaDP]

Check this out: http://www.radiationproducts.com/bricks.htm

Oh man, their interlocking radiation bricks look spot on. Still trying to find out what alloy they're cast from.

Has anybody had experience with these? Looks like it'll at least be good for pistol bullets. If I can identify it, it may mix in well to my pot for big BPCR bullets which I keep to known alloys for repeatability.

Are there any simple tests I can do to get any information on the alloy? I don't have a hardness tester.

[PanaDP]

I found many suppliers of lead bricks like these ones and most will supply pure lead or "hard lead" which is usually left vague but a couple suppliers defined that as 4% antimony.