does an x valve improve effieciency at all? to make a long story short, some candian guy (a customer that was at this pro shop) told me that you could get about 10% more shots to the tank because the x valve had better air flow as opposed to the older style retro valves, which is what i have. (i didn't believe him, he sounded like an idiot. told me that a 72/3k would hold more than a 68/45 because it is 4 inches longer...

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and please dont tell me that effieciency doesn't matter... i just wanna know the answer to my question.