for the sniper barrel i hollowed out the barrel in 3D Builder and put an extendable black selfie stick in it for the sniper attachment ,(link below), for the grenade launcher i used an Advil bottle with some decorative PVC pipe with a screw that attaches it to the baton (barrel). if you use the sniper attachment i linked below then print the hollowed out barrel(i have both the hollowed and original in my stl. file https://www.amazon.com/gp/product/B00QX0ETTE/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1 Luxebell Selfie Stick Telescopic Pole Pocket Purse Size with Phone Clip Holder for Gopro Hero 5, Session 5, Hero 4/3+/3/2 and Cellphone 6.6"-18.1" (sorry the pictures are upside-down