and put cans on them. the plastic lowers cant take much full auto firing, but they were good enough to get product hat was worth about 6k each in today's money. :-) it only took 3 welds and a bit of grinding. The mac 10 convertion was much more difficult, cause I had to make the sear a sort of rectangular bit of tube to fit around the maazine. They had a very high rate of fire, about 20 shots per second. My own design, i deliverately slowed down, to 10 shots a second. They were really controlable with the can mounted on them.