I use a kelty frame with no bag on it,it has a pocket for a water bag and the wrap around wings with straps,the fold down ledge is perfect for supporting the weight of an elk hind quarter or a boned out deer.
It probably depends more on factors like type of activity, length of activity, and weight to be carried (ie the backpack needed for an afternoon hunt would greatly differ from a two day hunt) I personally use a small pack that hugs low on my back for hunting. For long trips I pack in a external frame North Face pack. The bag is removable from the frame, so you can haul items like firewood or a deer quarter or whatever.
i am mainly talking about large backpacks not day packs. I have used the same internal frame pack for years and have used it for backpacking. I was just curious what others have used. I have just slid the meat into the pack and away we went.
This pack would be used for backpack hunts and to get game out of areas that you can't get horses to.
The #1 question in my mind when deciding what pack to use is what it'll be used for. I can't imagine an internal frame pack when hauling out meat. Aside from the shape limitation, you'll very likely be stuck trying to get blood out of the fabric. Externals can't be beat for hauling meat because they're so versatile in terms of strapping an odd-sized object, and they're easy to clean afterward.
However, if I'm just lugging essentials around and not taking meat out with it, I much prefer an internal pack that moves with me better and doesn't make me feel like I'm strapped to a headboard.
I have actually found internal frame packs are awesome for packing out meat. Just drop the quarter in the bag, tieten the side straps and start walking. I have had elk, mtn goat, rocky mtn bighorn, moose and muley in my internal frame.
Over the years I have seen several elk and deer hides left in the woods by hunters and I have to wonder why they do this? I fully understand and agree about getting the hide off the animal as soon as possible to cool the meat, but why not pack out the hide with you and use it? As far as I know there are no state laws that require you to take the hide home, but to me why waste such a beautiful part of the animal? Some might think they have no use for the hide or it costs too much to tan....