"The method I use is nearly identical to Whitebear's. If memory serves me correctly, I first read of this in an article by John Bivins in Rifle magazine."
I got the idea from Max Vickery in an article in Muzzle blast. He was hunting squirrels with a .32 flintlock Bedford. This was in the late '70"s or early "80's
if anyone has a copy of this article I would love to read it again.