One you must be on that crappy toxic server SS, I take people into SM ops all the time under 320 because most SM OPS its just basic mechanics to beat the bosses. I would not suggest taking an entire OPS full of people in 306 or less, because there still are some heal, tank and DPS checks that you simply can't do is sub 320 gear. Same as for HM OPS, the checks in place virtually require you pretty much have at least 326 none Noble gear.