10-22 Barrel Retention V-Block V1.0.1: Laffs Dynamics Self explanatory. Once barrel is pressed in the receiver, install this via two 12-24 V-Block bolts. (Can be found on Amazon.com) Idk, its a friggin V-Block. Waddaya want from me; an instructional DVD? Just print the damn thing. Update V1.0.1: Updated recommended printing materials, changed recommended print settings for better device strength, updated name of designer. Filament Recommended: Glass Filled Nylon, Carbon Fiber Nylon Print Settings: First Layer Print Height: .20mm Standard Layer Height: .16mm Wall Thickness: .40 Wall Perimeters: 8+ Infill: 60%+ Support Material Percentage: 20% Hardware Needed: 2x V-Block Bolts