I have been missing a good, realistic, over-the-sights shooter for a while. I played the BF mod, "Forgotten Hope" for several years. A free "realism" mod for the Battlefield series, it removed almost all the arcade features of the game and provided realistic uniforms, vehicles, and weapon effects.
As well, I was into WWII Online for a while. Likely the best armor simulator out there at the time. Good flight model too...
Likely the most-realistic shooter, but it's pay-to-play and a real time-sucker....
There is not much available. The "tactical" shooters have a high degree of realism but also require a great deal of planning and team coordination... Too much for my old skull.
Everything else I've found is obviously for the kiddies; strong arcade elements with lots of "leveling up" and "unlocking" better weapons and such.
In WWII online, there was none of that. As you gained experience and rank, you could have access to different weapons... That was pretty much in line with real military experience. You start as a rifleman. Other options later on included the machine gun and the submachine gun, but these were standard weapons with only a limited number available at each spawn point.
You had to attain the rank of sergeant before you could spawn an anti-tank gun or an anti-aircraft gun. I spent a lot of time poking 20mm shells at those pesky British ground-attack aircraft!
Best looking military shooter I've seen so far is ARMA II, but my rig won't run it. Guess I need to sell some more bikes....