Rooies, I'm curious as to the outcome of this endeavor. Regardless of what Solid Works or other CAD programs might tell you about the possibility of engineering a check vale, I have the suspicion that when you reach 12fpe the barrel is going to become inaccurate. This a CAD program will not tell. Guess the proof of the pudding lies in the eating
Robbie here on the forum has gone through the pain and lengths of converting an Anschutz 6Fpe rilfe to 12fpe, only to find that the barrel was actually designed for optimum accuracy at 6fpe.
I suspect that barrel grooving and twist rate is optimised for a specific pellet speed when it comes to 10m precision rifles.
The results from your experiment will shed some light I hope.