If there's anyone else like me that doesn't like having to hold the mouse button to aim, I found a simple fix.
Go to Documents /mygames /farcry 5, gamerprofile xml right click, select edit, Find weaponaimtype="0" change to weaponaimtype= "1" save and exit .
No more holding the button, always good to make a backup copy in case you screw something up : )
It's 12 lines down on the right.