Picked up the parts at ace in Gunnison today and it works good. I saw this on YouTube, and I have some rocks I want to crush.
A few wacks with a hammer sure speeds it up but watch out for back blast, wow!
Wear glasses, and don't look down the barrel while in use..

Looks good. Now, to help dealing with shrapnel and loss of ore, try draping a t shirt or neckerchief around the smaller pipe so that you can hold it and like normal but that it also covers the bigger pipe, too. And do not inhale the dust.