Er - “keyholeling” isn’t something that is supposed to happen. It means the bullet is not stable when traveling. I wonder if you used too light or too heavy of bullet for the rate of twist of the barrels rifling. It can make a significant difference.
“Everyone has a plan until they are punched in the face.”
Of course everyone trains to shoot at targets, but evidently their analysis from WWII and Korea is that a lot of shooting is just return fire in a general direction. Of course this greatly differs on the type of fighting you do and where. Vietnam especially they often couldn’t see through the jungle. I remember a combat vet came to our school once and said that almost all the time, you couldn’t see what you were shooting at. You could see the leaves move so you know something was over there from the bullets coming at you.
Anyway, yes, starting with the German St44, which is what inspired the AK-47, they moved to shorter, smaller rounds to allow each soldier to carry significantly more ammo. The Russians further scaled their AKs down to the AK-74 which uses a 5.45x39mm. IIRC standard load out for the US is 210rnds, but often they would carry more.
Your opinion is not alone, and there was A LOT of resistance for the switch in the 60s/70s. Couple that with the fact that 1) they used the wrong powder and didn’t chrome line the barrels and 2) didn’t tell troops how to properly maintain their new M-16s, and you were left with a very negative opinion of the new rifle who were introduced to the M-14 first. Even today I have read some modern reports that complain that the 5.56mm is anemic in performance. But given it is either 7.62 or 5.56mm for NATO standards, it is either/or until they decide to standardize something else.
Feel free to follow up with a PM.
