240 shots doesn't sound out of the way, in fact it sounds fairly low for the size of cylinder which looks quite large and the fact that by the time you're down to 40 bar I'd have expected the accuracy to suffer so you'd probably want to lose some off that figure.
Morini CM162's do 200 regulated shots on a much slimmer cylinder before the low pressure lock cuts in around the 90 bar mark.
Otherwise good shooting - I guess the only way to better it would be to upgrade to a 'Wobbly'... (see the collectables section boys & girls)