I suspect that the discrepency between the expected co2 weight of 20oz and the actual weight of 0.52kg ( 18.34oz ) is due to a disparity in the European and American legislation ... I.E. They are 20 oz American paintball bottles but to comply with C.E. directives they are stamped with our European fill ratio.

Your bottle has ... or should have ... a Pi sign stamped on it to make it legal for use.

Pi sign http://upload.wikimedia.org/wikipedia/commons/thumb/2/2e/Pi-symbol.svg/180px-Pi-symbol.svg.pnghttp://upload.wikimedia.org/wikipedi....svg/180px-Pi- symbol.svg.png

(Message edited by woody on December 26, 2007)