Those have been around for awhile. They work with any old 40mm shell. A few of the guys from CA will have them at OP RO in November. Its like an M203, but bulkier, heavier, and clumsier, plus its just something else to flop around while you run. The guys in CA put foam "rockets" in them and can reportedly get them into a window at 250 feet. It should make for some interesting encounters!