Quote Originally Posted by ccdjg View Post
If there is any interest I will post the results of my messing about, as my wife delicately puts it.
“Messing about” methodically and then writing it up is how all the best science is done!

I will be very interested to see how these work out.
Do you know roughly when these were available?
How much do your initial .177 samples weigh?

I guess that if the chalk disintegrates in the barrel and then several pellets are ejected then modern chronographs won’t be much good to determine muzzle energy. An old ballistic pendulum might work though.