I would really like to make a bannerstone, to put on my atlatl, so I could test out the theory that it silences the zip of the dart.  I can get hold of some soft slate quite easily, (I heard this was the material of choice), but I am unsure of how to drill a hole in it (primitively - I don't want to use a black & decker or anything) and basically how to shape it.  So any atlatlist out there who have any info on bannerstones, please pass it along.

What is a bannerstone? ???

It's a great big weight of easily carved stone (like slate or soapstone) which fits over the atlatl shaft, to silence the zip of the dart.  According to Atlatl Bob.  I just wanted to try out the theory.  Also, they look pretty cool.

Wouldn't the stone break after you throw it. Soapstone is pretty brittle.

You don't throw the stone, it is well attached to the atlatl shaft (not the dart).  It is just a broad weight to supposedly silence the zip.  Slate is also quite brittle.

any pictures?

There is one on www.atlatl.com, in the authentic atlatls section (or whatever it is called).  It is the big red weight on the eastern atlatl - although it is a bit odd that it is red, and stuck on in that way.  I think atlatl Bob uses unnatural materials for most of his weights.  

 And there might be some on www.atlatl.net.  There certainly used to be.