An improved version of Zheng3's penny ballistafor SEEJ. http://www.thingiverse.com/thing:23464 http://zheng3.com/seej/ Improvements: TODO: improve locking pin design, possible using A modification of http://www.thingiverse.com/thing:45737 improve rail design to make more durable and printableI printed at .1mm resolution with a raft, The rail may not work as intended if printing at higher resolutions. The locking pins can be a hard fit and may need a few manual modifications. The support for the knock are included in STL simply remove before use. Repair STL's before printing