Excellent report Robert.
The shots on the target are a great idea.
There's only so much a string can tell you.
And the main use of a air rifle/pistol is to hit a target!
I've also got a HiPAC and will be looking for the max number of sub 6fpe shots.
Just need to source a Fosters female coupling.
I'd like to see the reduced diameter transfer port seal you made.
What would the effect be using a 2300s valve with the reduced volume spacer.