John, I contacted RST last year for the same info. They told me:
20ga.
Ultralite 2-1/2" 1100FPS 3/4os were 6000psi
Falconlite 2-1/2" 1125fps 7/8oz were 7200psi

Hope this helps.
Bill

Last edited by ithaca1; 07/20/17 09:18 AM.
Bill Johnson