I prefer a dedicated backpacking pack for hiking with no intent of hauling out meat.
My go-to is a Kelty 65L Coyote. I tried a 50L and those threads were straining to keep it all in. Depending on season, I can do ok with 60 or maybe even 55 with some stuff attached outside but I hike a lot off-trail and having everything contained, not swinging around hooking branches, etc is a real plus. 70s and larger seemed excessive for me, lead me to carry stuff I truly didn't need just because I had room to carry it.
My favorite 60L is Granite Gear's nimbus access trace. It's a little heavier than some of their other packs but I really like some of the features. Might be out of production? The old Blaze AC 60 was also a great pack.
I still drag out my 1980 vintage Kelty Tioga II from time to time. The external frame is sweet for attaching sleeping pads, fishing tackle, waders or float tube, etc while still having cavernous room inside for food, clothing, sleeping bag, etc.
The only "hunting pack" I've used for backpacking and liked is Badlands' Sacrifice. It's about 60L. Tradeoff .. the back ventilation is crazy good, however, that pushes the load back changing your balance a little bit. I usually carried mine at around 32 pounds so it wasn't a big deal. One thing I really liked about this pack was the low profile for off-trail hiking, ducking under logs, limbs, and so on.
