250 Bar Valve On a 300 Bar Bottle

Personally No....
If it is not Rated for 300 Bars.... Don't use at 300 Bars
Never use any piece of HPA equipment and fitting beyond it's rating!!!

Stuart

Speaking of rating….. not to hijack this thread but-
Has anyone got paperwork for the small Carette filter offered by Joe B/Topgun-Airguns?
Just curious if it has been pressure rated.
I’ve asked them but can’t get reply
 
Using a 250 bar valve on a 300 bar bottle is fine. Ppl like to exaggerated and make it seem like you messing with a nuke about to go off. Yes hpa is dangerous but these pcp and bottle and valves are tested 3 times their rated pressure for safety. So using a 250 bar valve on a 300 bar bottle is only 50 bar different. Not even close to its bursting point which is like over 10,000 psi.