SpawnAmmo() function spawns random ammo regardless of parameters.

The reason being is in Build 1.28.159992, Scripts Rev. 114410
4_World\Entites\Firearms\Weapon_Base.c
line 965

FillSpecificChamber(m) doesn't include the other parameters.
Changing it to: FillSpecificChamber(m, 0, ammoType) will fix the problem.

Because you didn't pass a ammoType parameter, no matter what the ammoType is prior, it will always spawn a random bullet. Thanks.