No question about Vietnam it was a disaster.
But in other wars, they rarely lose soldiers and occupy the host nation with very less casualties.
vietnam disaster was compounded by NATO equipment failure IN vietnam.
I know plenty of vietnam vets- they ALL said the same thing - first thing u do when u get out in fied, is somehow kill a gook and take his rifle. or take risk of getting on the wrong side of some higher up if he ever sees you by taking illegal shotgun.
Why ? coz NATO rounds do not have punching power through thick foliage. AK-47 rounds do. so does a shotgun slug.
Vietnam is jungle terrain. its not open fields of europe or wooded treelands of europe to fight over.
Yankee machinery at the time was COMPLETELY LOATHE to admit that they were outgunned on the field at infantry level. Their solution was 'no problem, increase number of machine gunner per company to triple'. Well not everyone CAN be a machine gunner and its a good reason why there is only one per company and he looks like Hulk Hogan - coz you need to be Hulk Hogan to keep up running with your unit lugging a gun that weighs 15 kilos and 3 times more than every other guy's gun.
So in reality, the GI-joes just went 'sir yes sir, machine gunner sir' and then went around and scored an AK or a shotgun anyways.
And AK ammo is easy to come by in vietnam coz Vietcong made shit load of ammo catches thinking many will get busted and many did.
NATO rounds usually are smaller, but have higher muzzle velocities and greater range accuracies. Rus rounds usually are bigger, less muzzle velocity and lower range accuracies but only after 500m, which means only in very rare scenarios as you usually dont shoot your ARs at half a km distance very often. But Rus rounds can punch through close range obstacles a LOT easier - this is why TAVOR uses Rus round calibre at most missions, since shooting through glass, drywall, wood etc. is requirement for door to door urban warfare and CT missions.