
Have you fixed the firing valve problem that caused the "backwards recoil"?
Any idea what sabot material you'll be using for the tungsten dart? Tape just doesn't cut it for hybrids, I've found that out myself. I'm also a bit worried about your barrel; properly reinforced, it will take the pressure, but I've noticed another rather disconcerting effect on my reinforced ABS barrel - it is literally melting on high mix shots, and deforming severly when it does so. It seems like this effect is also thinning it at the breach side and causing deposits of solidified plastic inside the barrel which could interfere with projectiles' sealing capabilities on the way out.
Good luck on this build, I hope you get some cool damage pics out of it and no more drill bits driven into your fingers
