This is designed to clip a Nerf Jolt to a Nerf Tactical Rail. It also holds extra darts.
This clip is a redesign of Swift2568's Ammo Clip (http://www.thingiverse.com/thing:1479330). I liked his design but it wouldn't print in ABS on my printer (I don't have my overhangs dialed in for ABS). I redesigned it without any overhangs. I took out the decorative holes and beefed up the part thicknesses.