I just got an in-hand inspection of this coin and it seems to be lead or has a high lead content. I've never heard of this issue cast in lead, so I am contacting some experts I know as this is out of my expertise. However, there are some signs that the coin is made of bronze, but it sounds like lead when dropped onto a hard surface. It is about a gram heaver than most specimens.
There is definite evidence on the reverse that the coin was buried for a long time stacked with other coins, and that the coins were pried apart.
Are there any metallurgists on this forum who would know if a bronze coin with a high lead content (30%+) would have the same dull "clunk" sound as lead if dropped onto a table?
My pics:

