I'd say treat the ACOG like any other 4x scope, and the sight tower on top of it that allows for better aimed CQB shots should modify dice rolls.

Same goes for non-magnifying reflexive sights regarding the modifiers to the rolls.

Military/LEO reflexive laser or holographic sights typically run the gamut of 2MOA size dots or reticles that have adjustable brightness. Civilian or "commercial" sights are 4MOA. Example being the Aimpoint Comp M2 being 4MOA, and Comp M4 and Comp M4S(slight variant of AA battery housing placement on the device) being 2MOA.