National Lead Co.?

[fourarmed]

My 90-year old neighbor gave me 3 bars of lead mold-marked "111 National Lead Co. 111" These are 13"-long bars like solder comes in. He once worked at a government ammunition plant, and many of the rooms had lead floors for acid resistance. They had what he called a "lead burner" which sealed the cracks between the lead sheets covering the floor. These bars fed the burner.

I will eventually get around to measuring the specific gravity, but I'm wondering if any of the savants on the board know anything about this alloy.

[fourarmed]

I just received a PM from one of the savants, who informed me that the 111 alloy is 50% tin, 50% lead.