Why it matters
Aiming is a learned mapping between how far your hand moves and how far the crosshair moves. Anything that changes that mapping based on how fast you moved breaks it, because the same 5 cm swipe now travels a different distance depending on how hard you flicked.
That is exactly what mouse acceleration does. Raw input takes the operating system out of the path, so the game sees precisely what your hand did.
The two Windows settings to fix
- Enhance Pointer Precision: off. Despite the reassuring name, this is mouse acceleration. It lives under Mouse settings, then Additional mouse settings, then Pointer Options.
- Pointer speed: the middle notch, 6 of 11. That is the only position where Windows passes mouse counts through untouched. Other notches multiply or skip them.
How a browser trainer does it
AimBetween captures the mouse with the browser pointer lock using unadjusted movement, which is the web platform asking for the same thing a game asks for: raw, unaccelerated deltas. The crosshair moves exactly as far as the mouse does.
That is what lets practice in a browser transfer at all. A trainer that applied its own acceleration curve would build a hand-to-crosshair mapping that stopped being true the moment you tabbed back into a game.
How to tell if something is still in the way
Measure your cm/360 with a ruler and compare it to what the eDPI calculator predicts from your DPI and sensitivity. If the measured distance does not match the formula, something between the mouse and the game is scaling your input, and it is almost always pointer acceleration.