that or you need an expansion chamber for the paintball cylinder.
i played a lotta paintball a dozen years ago, and to maintain CO2 pressure and shot velocity, you wanted a gun with an expansion chamber so the CO2 could convert from liquid to gas in that chamber, THEN be released as energy on the bolt action. Especially for remote CO2 setups (bottle on hip with a gas line to the gun).
probably easier to get a 5-20lb CO2 cylinder though and a regulator that can handle your specific task.
Primary: English Mild
On tap: Pale Ale, Lancelot's Wheat, English Brown Ale, Steam Beer, HoovNuts IPA
Bottled: MOAM, Braggot, Raspberry Melomel, Merlot, Apfelwein, Pyment, Sweet mead, Cabernet
Gal in 2009: 27, Gal in 2010: 34, Gal in 2011: 13, Gal in 2012: 10