I bought a K4 5000 last year and have used it for 1 overnight hunt and a bunch of training hikes. I will say that it can handle 40lbs loads quite well. For the overnight I pretty much filled it but I needed to carry 5L of water and some warmer clothes, and had some luxuries to share with friends. I didn't use the lid on that trip, though. 15 miles and felt great at the end, no fatigue from the heavy load (started around 40lbs and ended around 25lbs).
Unlike others, however, I do not find it to be a great daypack, at least for archery. I don't think it excels with light loads, it sort of "floats" on my back and restricts movement. YMMV. I think it's an excellent option for overnights and the only reason I won't continue using it is if I upgrade to the K4x.
Unlike others, however, I do not find it to be a great daypack, at least for archery. I don't think it excels with light loads, it sort of "floats" on my back and restricts movement. YMMV. I think it's an excellent option for overnights and the only reason I won't continue using it is if I upgrade to the K4x.