A helmet is more of protective gear. Therefore it has to be the right fit to do the job it is supposed to. A properly fitting flight helmet should usually be a little tight to slide on. However, it should feel comfortable and snug once it’s in place. Try yanking the helmet up and down, side to side, by way of the chin bar. If it pulls your head around with it securely, then that’s a proper fitting flight helmet. The bottom line, the helmets should fit you correctly and shouldn’t make you feel uncomfortable in any way.