Genelang,
I haven't personallytried this method to remove Berdan primers but it makes sense. You fill the empty casing about 3/4 full of water and then take a hardwood dowel that fits snugly in the shell and finally place the shell on a piece of wood over a small hole drilled in the wood slightly larger than the primer. You push the dowl into the casing and give it a sharp rap with a hammer and hydraulic pressure from the water will push the primer out.
I hope I've explained myself okay, it's easy to invision but hard to explain.
Steve
