Ammo Carbine Buttstock (ACB) by FFFTech/FFFTechnology A buttstock designed to hold a reserve 10rds of 5.56x45 NATO ammunition, as well as having extra space above to hold small spare parts. The buttpad attaches via an indexing notch at it's bottom, and elongated indexing tabs at its top that matches with indexing notches in the buttstock. This buttstock is designed for Milspec Carbine Buffer Tubes only. Printer Used: Monoprice Maker Select Plus Filament Used: PLA+ Print Settings: Extruder: 204C Bed: 54C First Layer Print Height: .24mm Standard Layer Height: .20mm Wall Thickness: .40 Wall Perimeters: 3 Infill: 32% Infill Pattern: Gyroid Material Flow: 101% Support Percentage: 12% Hardware Needed: 1x M8x8 Hex Socketed Set Screw Installation (Do I really need to explain this...) 1) Press the hollow socket of the buttstock on the end of the carbine buffer tube. 2) After making sure the set screw hole is lined up with the end of the adjustable stock channel, thread the set screw into the stock. Use purple Locktite on the set screw if you're worried about the screw backing out.