Well I'm not max light yet but getting there I hate to say it but you may want to look into doing IB or ToO to get better light gear and if the perks don't fit your load out the infuse them into the gear you like. I did IB got 312 ghost and gear the first time when I hit rank 5
I have never had a 320 drop from Iron Banner, ever. That is 3 characters, rank 5, every event except the first year 2 Iron Banner. I have completed the Heroic King's Fall raid many times, I have had 3 320 drops that were none challenge mode drops. I guess at the rate I am going I will get there but I fear when I do the next DLC will drop and the grind begins all over again.