Buttstock stop pin for mil-spec 6 and 4-position stocks. Might fit Airsoft if using a standard buffer tube extension. Used for setting a stop position so you can grip and rip instead of fiddling with your stock. Works for mil-spec buttstock, Magpul, and MFT Minimalist stock. Probably works for other stocks that fit mil-spec tubes, I just don't have any others.

Recommend printing at 100% infill with 8 walls, top, and bottom. Also recommend printing on a side as shown in STL. That way the layers line up with stock motion for the most strength.