Having actually used both 5.56 and 7.62 NATO along with the 30 Carbine and 45 ACP in hotly contested adversarial situations I know which one I would rather have regardless of the engagement distance. I have also seen the immediate end use results of the 30-06, 7.62x39, 9mm and 7.62x54R cartridges on friend and foe alike. All were with FMJ ammunition.
In my last deployment they kept trying to give me an M4A1 because it was easier to carry and get in and out of vehicles with. I told them I would take an M14......that got me a "deer in the headlight look" so I just kept my M16A2. I did not feel undergunned with it but I was not in an offensive posture.
In a non combative environment I have shot numerous critters with all the afore mentioned cartridges using soft and hollow pointed ammo.
While I have 3 ARs in 5.56 and a 9mm CZ75 in a SHTF scenario it is my M1A in 7.62 NATO and M1911 45 ACP that will go out the door with me.
"7.62 NATO.....better than Master Card of VISA......accepted worldwide.....never leave home without it......"
"What is cover to 5.56 is only concealment to 7.62 NATO...."