The Hensley & Gibbs 79 31. Found it at a gun show recently and took it home thinking it was perhaps a gas-check express boolit for hot, +P+ self-defense loads for the .32 S&W or Colt Short.
However, on researching the numbers, I find it was made as a boolit for .31 caliber cap&ball revolvers. What I thought was a "gas check shank" is a taper allowing it easy entry into the chambers. They made a .36 caliber version and then cut a cherry for this version in 1944. I can't imagine that they wore that one out; what kind of demand for boolits for obsolete pocket revolvers would there be in the postwar era?
I usually don't like calling bullets "pills," but if ever one deserved the name, it's this one.
Maybe I ought to dust off my ASM Baby Dragoon and wring them out.