4Game

Recently made a post about why I dislike the turn rate reduction mechanic and it was brought to my attention that people are not aware of how the mechanic works.

Turn speed reduction on equipment reduces your un-scoped sensitivity (left most value in the settings), by the total reduction percentage of your equipment. It does not reduce your sensitivity when scoped in at all.

If you are using a DPI toggle on your mouse for items like altyns or zabrallos and raising your dpi by a large amount, your scoped in sensitivity will be through the roof. You are better off changing the left in-game sensitivity setting or you need to remember to toggle back when you plan to scope.

Adjusted un-scoped sensitivity: 
New Value = Normal sens * (1 + total reduction/100) 

You can actually simplify this to work it out in your head very easily depending on your Normal sense.

My Simplified formula: 
My Normal sense = 0.3 
New Value = 0.3 * (1 + total reduction/100)           
= 0.3 + 0.3 * total reduction / 100           
= 0.3 + 3 * (total reduction / 1000) 

So if my total reduction is 25% I can easily just think 25 * 3 = 75 and therefore my sense should be 0.375. If reduction = 3% then sens = 0.309. You can do similar simplifications with all sensitivities but it's easier if you only have a single significant figure in your starting sensitivity or if you round off.

Tarkov doesn't allow 3 digits of accuracy but I believe you can change it precisely in the config files (at your own risk). I just round off to the closest hundredth as it's accurate enough for my taste.
Disclaimer: If you don't care about variable sensitivity at all, more power to you. I can't stand it personally.

TLDR: Nerd stuff = DPI button bad.