Originally Posted by shiftsup
I am going to assume that my LNIB XM had an air seal issue that was causing the 330 fps that was corrected when this new hop up unit was installed. There's no way that two O rings alone are going to make a 20% increase in muzzle velocity.
Actually, 310-320 fps is the stock velocity for CA Armalites out of the box. Such a jump in velocity is quite perplexing.
That being said, I've had several guns where simply replacing the hopup sleeve with a Guarder Clear has jacked my velocity 15-30 fps.