Err I'm not too sure, I haven't really done any measurements on that spudgun.
It really depends on how fast my ball valve is opening, im guessing 30-40ms max as I've never seen it taking more than one frame to open on video.
I just tried estimating velocity with ggdt, and it seems to predict 130-140m/s, but I could be way off as I don't accurately know chamber volume projectile weight, valve Cv or opening times

That seems quite low, especially compared to previous airguns I built, but I was noticing rather long flight times.
Damage on target is quite impressive but that might just be down to heavy stable projectiles.
Spudfarm those are massive !

Recoil must be considerable.
Nothing too interesting on video, I hope to get one done before next WE, but then after that I'm back off to the UK and won't be near any airguns for a while.