See: How I Designed This
Credits go to Ultrasonic2 for the handle: https://www.thingiverse.com/thing:2400385
and ehdrien for the pumpMid: https://www.thingiverse.com/thing:3031987
Just wanted to try out a less conventional design for my Nerf Kronos. This is the middle piece of the shotgun pump for converting the Kronos to a shotgun (instructions and other files provided by ehdrien).