This is an untested two shot shell for the Nerf Sledgefire. I plan to print it this weekend and may make some modifications to allow for extra airflow from the third air restriction hole in a V1.1. Let me know if you print it and how it goes, I'd be happy to make some modifications and if there are any other Nerf ideas that you want modeled let me know and I'll see what I can do. An arduino based chronograph will be coming soon. For other version see:
Original shell:
http://www.thingiverse.com/thing:2224993
Single shot shell:
http://www.thingiverse.com/thing:2230107