For those looking at external frame packs- on a budget. Look at Eberlestock Mainframe F1. Weight is 4.5 pounds, then add a Kifaru Camp bag 0.8 pounds in weight.
http://store.kifaru.net/camp-bag-4800ci78liters-p146.aspxhttp://www.eberlestock.com/miva/mer...amp;Product_Code=F1&Category_Code=BPYou will be into one of the lightest external pack/ pack frames available at under $300, and weight is 5.3 pounds.
Real world testing. 2014 -I had a hind quarter, both backstraps, with meat bag, and head with antlers strapped to the frame using only the provided straps. Trust me when I say it is tough enough to pack out heavy loads, I believe it will handle more weight than you can carry.