Lookup Hoffman Tactical on Youtube for testing videos. And the hose clamp is for additional reinforcement on what is the most likely break point on a 3d printed lower, but theres plenty of videos on youtube showing it shot without. The bolts for the front takedown pin is to allow a bit of flex to reduce stress on lower and is printed in polycarbonate. Ive already put about 350 rounds through it with no issues. The designer also has AR10 lowers