Hi all,

I visited an antique arms display in Germany, and saw a strange thing: Most of the long arms (not sure if "rifle" is the right word) had hexagonal (perhaps octagonal) bore, with semi-circular grooves in the corners of the hexagon. See the crapy diagram.

Now, there where always weird ideas and configurations. So at first I thought this may be an experimental form of rifling. But then I noticed the same shape was on wheel locks, flint locks and cap locks. So this configuration lasted for handreds of years!

Does anyone know what is this?

BTW, the handguns had a normal round bore.