Well assuming all of your other gear was 310 it shouldn't be able to drop too significantly, I'm pretty sure that you can damage anything within 35 leveled or so of you and 100 light is about 10 levels, which means the kvostav (5 attack) would only drop you about 30 levels. It would be counteracted by the other gear, and additionally, I'm almost certain that not every player going into the iron banner is going to have 310 light