First off: Credit to Kane for the prototype, coming up with the great priming system, and for getting me started in bows, and to Ryan for making a freakin' work of art.
Now, on to the much uglier version:
Like Kane's pump crossbow prototype, the catchface is at the rear of the plunger. It's all just pounded together CPVC, .5" and .75" PVC, and .75" endcaps.
I used a new slot making method this time: I drilled out holes, and then connected them with a sanding drum.
I used a slightly different method for the tee than Kane and Ryan. I used 1" PVC slightly longer than the length of the tee, and then hammered .75" thinwall into the ends of that, for a telescoping support system. .75" CPVC slides inside of that. I used the center seam of the tee to help place a 5/8" hole (air will be directed using .5" CPVC). That hole then was the guide to drill the arms.
.5" CPVC with .5" PVC for the reducing bushing on the plunger tube.
For the pump handle, I'm using two 1.5" couplers. A little loose, but they work fine.
The trigger is pretty standard: wood pin and a roofing nail.
I decided a stock would be a good idea for this one, so I added a removable one with a coupler and a chunk of PVC.
Overall, it needs a few tweaks. The pump handle needs to be a bit longer, so the priming hand doesn't need to go as far back. And I screwed up a few measurements during construction (that slot is way longer than it needs to be, to the point that I had to make a new plunger, and the overall blaster is about four inches longer than it needs to be). But overall, it works, and works well.
Edited by Carbon, 23 February 2015 - 11:31 AM.