How fast does a regulator reach equilibrium?

It's a Huma that doesn't require a drilled hole. Velocity drops by about 10 FPS if I fire a second shot quickly. I was hoping not to have to modify my tube at all, but I may try Huma's suggestion of filing a groove in the threads on the valve block.

I did leave the valve block loose in the air tube, as per the instructions. What I find strange is that the plenum is the same diameter as the regulator body, and the whole thing fits snugly into the air tube. Of course it's not airtight, but I'm also not convinced there's enough room around it for it to vent freely. Especially if the thin aluminum plenum swells at all from holding back 150 bar.

Here's a photo of it from the Huma site:



The valve block already has a groove cut in it from the factory that stops 1 or 2 threads short of the o-ring seat. I suppose this is a safety feature to empty the tube before the valve block flies off if you unscrew it with pressure in. I may unscrew it to that point and see if it breathes better. (Outside and not pointed at anything!) If that solves the problem, I'll extend the groove all the way to the o-ring seat.