Yes the whole Others and guns thing is confusing. It seems they have old WW2 style guns and Michael's assessment seems to confirm what many observed in the episode where he disappeared. And yet, they must've known there were guns in the hatch so you'd think they could've armed themselves whenever they wanted unless they were barred from the hatch and someone is inside guarding something they weren't supposed to have access to. Maybe they really don't need guns since Ethan seemed freakishly strong and agile. Obviously they're not impervious to bullets though, right Ethan?