1. use a 6.5mm or lower caliber weapon.

2. Shoot at an enemy outside of 200m (with 200m it seemingly does reasonable damage).

3. Observe how many shots it takes to kill someone and that helmets stop multiple headshots even if it hits an exposed face or neck if it is at or beyond 300m, although damage issues start as close as 200m.

Greatly nerf the damage and/or soldier protection. I believe most fans agree a system like Arma 2's where rounds often kill too reliably is much more manageable in a tactical game than a system that is not tweaked and balanced and results in rounds not being immediately deadly at all in many scenarios. In summation, enemies with 'glass jaws" are more conducive to a positive experience than bullet sponge enemies if we can't have an ideally realistic damage system.

Due to distance being the determining variable, perhaps the ballistics values on those rounds are too pessimistic?