I agree on the whole MBR parameters. Now that I am retired I no longer have to carry one for XX many miles I am a protagonist of 7.62. When I was a private and carried the m60, I loved passing off my pig for the M16 which just floated in my arms.
But really folks, when your target is hopped up on adrenaline they may not even notice the little bullet for as long as it takes to shoot you.
So my choice for zombie gun, was the HK91. Mine was built from a G3 parts kit from England. Guy in Ohio named Charlie Jones (pegasus ordnance) built it.
Study the roller-lock mechanism, which the Germans called "Half-lock" and you may see why they were so popular to equip untrained armies. This mechanism can be seen in the MG42 which burns 1100 rds/min. So yes, reliability and durability.
OK, the FAL is ok but I love my HK.