Imgur album here with more internal pictures: https://imgur.com/a/PixWTVO
This is a project I started concept art for in 2019, but never actually started work on until May of this year.
This blaster works via a front-primed plunger tube & plunger, with a bent barrel and sealed end that redirects air to shoot out of the stock 1995 Crossbow's barrel area. I used a widened Kronos catch with a 2nd catch spring, and a lever/linkage bar system to activate the catch. The linkage bar goes back to a polycarb trigger.
This blaster is getting ~150 fps out of an 8 inch CPVC barrel with 2/3 of a [k25].
If (when) I do this mod again, I will most likely use a Rainbow catch to use a [k26], perhaps a wider plunger tube, and probably integrate a brass breech onto the top (maybe with a 3d printed cover/casing/spacer?) instead of just a 1/2in PVC/CPVC coupler.