if your cross hair is compatible with v4 manager,
it's recommended to upgrade it to S1's firmware and APP by following this UPL:
http://www.reasnow.com/forum/index.php?topic=2575.0to catch up with the latest progress and update for R6.
once it's updated
and here are our recommendations for Rainbow Six: Siege(Updated)(v2.04)
firstly, please restore all your settings in this game and then change them as shown below:
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Options/Controls:
Vertical Sensitivity = 100
Horizontal Sensitivity = 100
Left Stick Deadzone = 10
Right Stick Deadzone = 10
Controller Rotation = Updated
Controller ADS Sensitivity = Standard
Standard ADS Sensitivity = 50
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