daxlw, it's hard for us to tell in you pics exactly what you have, but if it has the internal snap ring as described by others, a lot of time pressure inside cylinder will distort the groove that snap ring fits in, makes a burr on edge of snap ring groove. You'll get the snap ring removed, glad will move a bit, but seems to hit something solid and won't come out, that's where it's grabbing that burr on snap ring groove. I've had to really give some of those type cylinders a hard slide whack with ram and piston to get that gland to release. Once you do get it apart, be sure and sand sharp burrs/edges inside the gland area of cylinder with fine emery cloth.