Jagged alliance 3 aiming.

Hello I’m wondering how aiming works in this game?

I noticed a circle when choosing to attack. Is this circle similar to phoenix point where when I attack the bullet will hit somewhere in this circle (I somewhat highly doubt this since max aiming seems like a sure fire hit) ?

Or is this circle a general idea of how much each stage of aiming adds to the overall accuracy of the shot ?

If it says someone’s body is behind cover with the cover symbol except like the hand will I always hit the cover unless I target the hand? I heard this game has actually bullet physics so if someone is standing behind some sand bags would it be impossible to shoot their feet.

Overall I think the concept of this system is in theory kinda awesome I just need some general guidance of how it works.