fwiw - WPS makes the Yukon plastic frame system used in the Outdoorsmans pack systems, and also the Kodiak plastic frame used in some military packs.
fwiw - i bought a military pack system on Ebay - with the Kodiak plastic frame and the suspension and the pack bag (for about $60, if you're a patient and diligent shopper) -- and then I bought the Wilderness Pack Specialties meat hauler (about $25) to attach to the frame system for a dedicated meat hauler. Works great for me, especially for training by loading weights in the meat hauler. I'm not trying to take business away from WPS, just letting you know that their Kodiak pack frames are widely used in the military. (fyi - the military packbags that are available are heavy (Cordura), and not designed for hunting.)
fwiw - the WPS Kodiak frame works for me, but i'm short, i.e., 5'6". I expect that the shoulder stabilizer straps probably won't be very effective for taller people. (see, for example, see the load extenders on Mystery Ranch packs so that the shoulder stabilizer straps actually pull the whole load closer, instead of just the tops of the shoulder straps).
I also have an Outdoorsman pack (extended version of Optics packbag), with the Yukon plastic frame. It is a great pack. very easy to adjust, carries weight comfortably, good pocket systems for hunting, in my opinion. It is my overall favorite hunting pack (i also have a Kuiu Ultra that i use for backpack hunting, lighter weight but less comfortable and durable; Eberlestock JustOne; Cabelas Outfitter frame packs, etc.)
GLWYS.