I handled and shot an FAL a couple times. Not my cuppa Joe. First, the danged thing is too long and heavy. Makes my beloved CETME feel small and light in comparison. Second, that stock shape does not work with my ol' punkin' head. I can't get a proper cheek weld. Y'all can have them. I'll stay with something more ergonomic.
For the best 308 battle rifle, you also have to take in account the ability to completely disassemble and reassemble said rifle with the minimum amount of tools, try re-barreling a M1/M14/M1A, FAL, or HK/CETME with out a fully equipped gunsmith shop. With the AR series rifles, whether they are the AR10 or AR15 series, re-barreling requires a simple vise, receiver wrench and upper receiver block. The SCAR series is even more simple to replace the barrel.
If in doubt on what it takes to overhaul a rifle in the field then check out the wwll overhaul facilities. They would clear out an area to set up shop in some semi protected area, then find all the old, damaged and even buried M1's. Wash them down with the solvent they had, gasoline and rebuild those that were salvageable, save the good parts and reissue as needed. Odds were the barrels on most were OK as were the receivers. Just a matter of using what you have. Barrel Bad, bent in a fire? Simple vise and wood blocks along with the simple armorers tools was all they carried, spares were culled from the irreparable. Details? My Dad was a Jeep mechanic and often called in to work on what ever needed attention. Found this picture of Pacific Ops of a non depot repair center.