Interesting way to do it. It will be interesting to see it when it's fully assembled with the priming bars and everything.
Are the pictures showing it positioned on the gun, the same positions that will prime the blaster?
The forward position will be further forward but the back prime will be as displayed.
Cool mod. Personally I'd use a recon slide or something (or a premade pump) but it's very cool. Is it an internal priming bar?
I dont really have the funds for a premade grip (and i dont have all that many blasters so scrapping is out of the equation) No its not a internal priming bar.