Whilst walking the dog this morning to blow away last nights cobwebs I was crossing a shallow river and something caught my eye.
I picked out of the water what I thought was a musket ball. When I examined it with a magnifying glass I can make out rifling which I think consists of 7 ridges and furrows. It has been slightly flattened on one side too by an impact with something not too hard.

When rifling was first used, how many grooves were originally used and can a ball be dated from such information ?

Yes ! For those who know me my wife is an archaeologist. But she knows nothing about guns or militaria. Come on guys educate me let me be the expert for once.