I picked up a Mystery Ranch Selway last year and am astonished by the carry capacity and comfort of a true hunting pack. Most backpacking bags these days are internal frame, meant to carry weight up to 50lbs max, but do a lot better in the 30lb range. While most hunting bags are an internal frame by design, they carry weight like external frames of old. If you can find anything local to try on, thats your best bet for comfort. Unfortunately with the direct to consumer approach from many companies and most hunting stores being geared towards the budget hunter, finding these top tier hunting bags to try on can be difficult unless you have people near you to test theirs out.
