i made my own, and what fun i had with it too!
I did woodwork at school and kinda know how to use a chisel, i got a piece of 3" square wood (it was lying about) cut it off to fit my hand (laid my hand flat across it) rounded it off with a plane, and spent two nights wrapping my hand around it and chisling bits out, to make it fit the rifle i drilled a small hole all the way through the middle, then a bigger hole to about 2/3's of the way down, found a bolt to fit, put a washer down it and i was away, if you are at bisley next week, find me and i shall show you