Ok, how is this:
"Weapon (Ranged): Deals damage based on psi level.
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Pump: Increase psi by 1, reusable. Lose 1 psi per turn"
Then I can set the formula to scale damage similar to catapult.
Maybe have it max out at around 15 to 20 damage to keep pace with farenheight?
Fortune idea: "Today the sky is the limit... Just be careful or you'll shoot your eye out kid"