Rod I speculated upwards of 10 k since I dont know the source , nor the abuse the rifle has had , if the pins have walked enough to egg the holes and crap like that must be fixed 10 is about right . You have to remember tho that some want a true 16 , and some would rather have a dias ( drop in auto sear ) since it can go in many host rifles easily , and once you screw up a 16 lower bad your basicly done . The truely broke folks who just have to have fa in the ar platform go for the lightning links lol .