Scaled up by roughly 1.1022x, to make the rail gap wide enough to fit onto my AR-15 quadrail. (I have a 9.675" YHM Lightweight Specter Quad Rail, Free Float ) The original measured around 18-19mm across the gap, and my rail measured around 21-22mm across, thus the need to scale. Update I've been using this thing on my gun for almost a year, and it is still solid, after 2k+ rounds, carrying the gun around by just the foregrip, and using the foregrip as a bench rest. No signs of damage or cracking yet. I believe I used 70% infill on the print.ABS @ 230C Bed @ 120C Full support + raft Infill: 70% recommended, and wouldn't go below 30%