Gun unlocks and their uses?

[jrgl_cuchallain]

Unsure about this but can anyone explain what all of the various gun unlocks do (obviously i can guess what things like the silencer/bayonet do). In particular what does the k-98 winter trigger do (not even look nice?) and the second unlock for the svt-40 do (something like advanced muzzle break).

If possible could I get a full list of what every upgrade does?

 

[Nilzey]

Winter trigger guard
Nothing at all! It's just pure cosmetics.

In reality it was used to provide soldiers with the ability to use mittens whilst shooting