Hey Eric, welcome to CP!.... The windows on our 2520 open without much effort, but they don't open/slide back as far as one might expect. Ours are the 'Taylor-Made' brand window; (there is a Taylor-Made emblem etched into the glass of the lower aft corner of the window).... You probably already thought of this, but before spending a lot of $$ check the tracks for debris that might be stopping/clogging up the slide. Next try spraying some liquid/spray silicone on the upper and lower tracks to see if that helps.... I'll get on the boat today and measure how far back ours slide so you can have something to compare yours to.