You can buy a used .30 caliber Impact, do a few relatively simple mods and have it shoot the speeds and energy you want for cheap. Shot count goes down considerably, but speeds at 170 bar are constant in the 970fps range.
- Add a 6-7 gram brass hammer weight,
-Change the C3 o-ring bumper to delrin or similar,
-Port and polish the valve housing's transfer port along with the rear block's transfer port
-Enlongate and give a venturi shape to the brass transfer port,
(The end results here are to have all three ports match up when installed),
-open up the valve seat to 6mm,
-Shoot and tune for accuracy (not shot count)
Additionally, putting on the extended plenum tube and larger 6.5mm valve seat and stem seal adds to the shot count and lower reg pressure.