Just adjust the reg pressure, can't be that hard.
Also check you don't have a buggered transfer port / leaking port. Also remove the barrel and see if it has a very tight choke, burred TP, etc.
the valving would be designed to work around 70-80 BAR, so it's going to be prettty crap and need a relatively huge amount of hammer at 200 BAR, so not a great idea if you are not adept at doing mods (and if you are, you'd just adjust the reg).
Always looking for any cheap, interesting, knackered "project" guns. Thanks, JB.