I just looked at Del City's website (which has some great items and awesome prices by the way) and didn't find it - but it almost looks like a .22 caliber pistol shell casing. I'd agree, a simple ring terminal would probably do the trick, but a .22 might be closer to the right dimensions (wall thickness etc) plus it already has a flange on the bottom. Just slip a ring terminal over the top, solder together and drill out the primer (which has been expended already) - drop by your local range and you could probably pick up a handful.