Go get your foot fitted by a boot fitter. First off, you are not a 30, you're probably a 29 or maybe even 28.5. Shoe size doesn't correlate to ski boot size because you probably have the wrong size shoe to begin with. You go by whats super comfy, thats not what ski boots are supposed to feel like. To put it in to perspective, I wear a size 9 and a half shoe but wear a 26 boot. Go see a boot fitter.