Hey guys

I am losing air (fast) out of my Rapid MKII. I filled it up to 232 BAR and went out shooting. I shot less than 10 shots and the next morning it was completely empty! On removing the bottle the air was coming out of the valve but when I refilled it the valve was seated and nothing was leaking..... I presumed it was the bottle but perhaps once the pressure dropped to such a small amount it may not be enough to seat the valve closed?
Could it be the O ring seal or something within the action causing this? No one I know has a rapid to try another bottle out.
Cheers
Si