Hello,
I took a .250 thick square tube and cut it 6" long then took a brass ring and drew the ID and OD then cut a circle out of the top. The $10 strikes fit perfect. I then take a hammer and chisel and knock the center out. It only takes a few seconds and usually 1 hit for each piece. Since the tube is .250 thick I do not have to worry about damaging anything (except my hand when the hammer slips LOL).
Sarge SS-885