One of the simplest reasons 77-grain ammo got exposure to the US Army Special Operations Command is the fact when Afghanistan-bound 5th Group came to the AMU immediately after 9-11 we already had pallets of 77s on-hand for the 2002 competition season. There weren't enough homogenous pallet lots of ammo (69s, 73s, or 75s) to load 55,000+ rounds on the truck.
What was on-hand was mixed lots of Federal 69s, Black Hills Berger 73s (the most accurate), and mixed plain and moly Black Hills (Hornady) 75s. The 77s were the quickest single-lot number we could issue out without having to worry about Soldiers having to mix and match zeroes between heavy and M855.
The 77s are good ammo, and have proven themeselves. We continuously check ammo, by lot, to ensure the shoot the most accurate groups at 200 and 300 with match rifles, and all the way from 600 to 500 and 300, rapid-fire, when fired from short-throat M16s used for Infantry Trophy rapid-fire matches (the "Rattle Battle").
I don't understand folks who grouse about the shortage of one heavy 73, 75, or 77-grain lot of their "Boutique" load. Any patient, competent handloader should be able to duplicate production recipes with a little work.
Hornady custom loads commercial 75-grain Match, and I doubt you'd notice the difference between it and the Army 5.56mm contract load (much like the 168-grain 7.62mm match loads they made in the early 90s).