One thing pops out at me right away is that UL 50 liter packs aren't designed to carry 50 lbs. If you're cutting weight in the pack itself, I think mfg.'s just assume (and quite rightly) a lighter load to be carried. I have a few light, but not UL 60l packs that I feel aren't meant to handle over 35 with their suspension. I could probably carry more in them, but not for more than 5 miles w/o pain. I would seriously consider weighing your gear and going over the gear lists of other BP'ers. For myself, I'd be packing the Flash 50 with no more than 25 to 30 lbs.