To begin with, I wanted to say that I love stats and math (engineer is my job), so no one forced me to do this. That being said, I have a few statistics to share. (I am not an English native so excuse me for any grammar mistakes)

I recently saw a post on this reddit asking about First Shot Accuracy and I wanted to experiment to see if it was that bad of a feature.

I took notes from the wiki of each primary weapon's FSA. I excluded shotguns, SMGs and Frenzy and also sniper rifles. To explain myself, I know that shotguns, Stinger, Frenzy and Spectre are close range weapons and I hope no one here needs statistics to learn that.

Now, here's the funny part. FSA is the value in degrees of the angle between where you aim and where your bullet will land. Here's a small drawing to explain it :

TRIGONOMETRY. And right about now I've lost the only two souls reading this. You can scroll down to see the results of the experiment.

So, by using Trigonometry and more precisely the tangent formula, we can know the exact deviation of the bullet from the crosshair in meters.

With the best software which will not be named, we can know the dimensions of the players in the game :

I measured that green Radianite boxes were 2 by 2 by 2 meters so our Sova here has a height of 2 meters. By using cross multiplication using pixels we can now calculate the head width in game (scientific accuracy is a bit off here but we don't have many tools apart from that).

That being said, here are the results :

The dotted line is half a head width as measured earlier. Any weapon with a bullet deviation higher than that, bullet has very few odds reaching the head.

So, to go back to FSA, any weapon which has a deviation from the crosshair higher than 0.19 meters is not to be used at that range.

Conclusion is, if your crosshair is right at the middle of the head, unless you in a situation over this dotted line, it's not FSA's fault you're missing your shot.

But if the crosshair is on the edge of the head, it's another matter...

We can also conclude that past 40 meters with Vandal, it's better to ADS as it decreases FSA and zooms in also, but I'm sure everyone knew that.

Not sure if anyone is going to be interested by this, but if it's the case, tell me what you think about it, and to my fellow scientists, I'm not the best in trigonometry so I could be totally off there please tell me if you see any errors.

EDIT : some few mistakes people pointed out were corrected thank you for helping !