You dont understand. Asymmetry is not necessairly one side having unique weapon and another side having another unique weapon. Instead one side can have advantage at one thing while another side will have advantage at another. For example germans should have MGs providing a lot more dense fire while soviets should get SMGs with a lot higher ROF and larger magazines. This will give different advantages to sides, but that doesnt mean that soviets must not have MGs or germans must not have SMGs. This is definitely not what twi thinks according to their asymmetry in RS because they gave lots of knee mortars to japs while americans dont have any player usable mortars at all, like they didnt have small mortars in real life.
https://en.wikipedia.org/wiki/M2_mortar
Japs also had type 100 flamethrower, they may be didnt have as much of them as americans had but they still had and used them.
So i suppose they will give unique flamethrowers to vietnamese or something else unique since they made asymmetry so radical in RS.
Are you really going to compare the 19kg M2 mortar against the 5kg Knee Mortar? That's comparing apples to oranges.
On topic however, the Vietnamese should not get flamethrowers, that's ridiculous. What the NVA and VC however did use, was the RPG-2. From what I've read, one RPG-2 per squad. Of course, this only fired a HEAT projectile, but still, that does not mean it is useless against personnel.
As to the amount of ammunition carried with these weapons, the RPG-2 had two men, one carrying the launcher and 2 grenades, and the assistant carried 3 grenades.
The M79 grenadier would have carried his ammunition in a claymore bag, or the dedicated 18/24 round vest.
So yes, all in all, the M79 is a potent weapon, but I imagine it would take considerable skill to aim it at longer ranges. And the grenadier would only be armed with a pistol, so given the safety mechanism of the grenades, I'd say he has no chance going up against a Type 56 armed VC at close range.
Edit: The M576 round could be added, but according to Wikipedia and its sources, that'd basically make it a weak 20 gauge single-shot shotgun.
