Short barrel, small plenum and standard valve...
I have an .22 AF Talon SS that had those properties.
Wasn't too bad. I fixed it 12" barrel -> 19" barrel
300PSI unregulated bottle & valve -> High flow valve, Huben Cricket Max-ATH regulator, 1.1L Acecare Fat bottle
No plenum -> MAX-ATH 50CC plenum
Stock 49g hammer -> 90g hammer
Stock 1.5x25x100 spring -> 2.0x25x100 spring (that number is a guess, I never measured the heavy spring)
When I cranked up to regulator to 3000PSI and the power wheel to 10 I got
1100 FPS & 70FPE with Apolo Monster 25.4gr pellets.
Now I run 1800PSI and get around 850FPS & 45FPE
as Carol Shelby once said when questioned about moving from the 289 to the 427 in the Cobra.
"Doesn't the 427 have too much HP, wasn't the HP in the 289 good?"
"Well, if a whole bunch was good then too much must be just right"