1. Spawn on the Livonia Server.
2. Get to the red 2 story building on the hill near Nadbor plant (it is from the north side, up on the hill, there are also garages behind it and a small shed if look to the south).
3. Get on top of the shed ad look in the big yellow car direction (south east direction, to the left from the plant, another hill that is located right behind the plant to the left, there is big yellow truck on top of it and a helicrash spawn site).
4. Measure the distance with range finder to that truck (you'll need to have range finder with charged 9v bat)
5. Spawn any sniper rifle from the list : Mosin, SVD, SV98, Tundra M70, Savana, M14 (SVD and M14 are marksman rifles but still)
6. Spawn best possible scope for the rifle that you chose (PU / PSO / Acogx6 / Hunter scope)
7. Spawn a player right near that big yellow truck so you could have visual on him. (a player shoud wear no clothes at all to produce lowest possible protection from the caliber that you gonna use)
8. Try to kill that player (doesn't matter how many shots you gonna use)
Expected result: not a 1 shot kill, also not a 1 shot ckock out.
Now project this on the real game with real players, and if this test won't help to ubderstand the problem try to repeat it with a real player instead of spawnd npc player.