Modern combat optics are becoming more and more advanced.   Back in the day people just used the European pole or standard crosshairs for rifle scopes, but not anymore.   These days combat optics may be red dots, green dots, illuminated reticles, bullet drop compensators etched in glass or Mil-dots.   Combat optics like IOR scopes may have a reticle that is almost a sizing guide for range estimation where you just simply hold the target into a range estimator and then make adjustements on your target knobs or just  hold over.
There is also something completely unique.    Eotech holographic gun sights.  These unique combat optics have a holographic gun sight that, once sighted in, will stay sighted in no matter how you view through your sight.   According to many of those that we have spoken to in Iraq and Afghanistan, these are hands down the best CQB gun sight.  With zero magnifation,  you have the FOV that is unmatched by normal rifle scopes, and with that, comes faster target acquisition.    The unique holographic gun sight looks like something that was used in aircraft gun sights.   There are also options that can  be used for some level of magnification so that identifying targets at greater distances can be done without compromising the close up speed that these optics give you.