NonWonderDog has released on the BIS forums, a Realistic Ballistic addon. this addon will make ArmA more realistic when shooting at long ranges.

here is what NonWonderdog had to say about this outreagously cool addon.

First of all, huge thanks to Kronzky and his portable target range.  Without the ballistics tracking in that script, none of this would have been possible.  

You know how the supposed difference between the ArmA ballistics and the VBS2 ballistics is ArmA's lack of bullet-specific ballistic coefficients?  Well, when poking around in the data files, I found that the "airFriction" parameter can be set per bullet type. After a little research, a little ballistics calculator work, and a whole lot of tweaking, I've managed to create proper exterior ballistics for each small-arms bullet.

Rounds now drop much, much more, particularly 5.56 mm and 5.45 mm rifle bullets.  Since damage is dependent on speed in ArmA, that also means that body armor has no problem stopping rounds past 500-600 meters or so.  You'll still take damage, but not much.

If you want to see exactly how they compare, I've got a comparison spreadsheet here.  There are two tabs, one for my ballistics, and one for stock ballistics.  The first graph on each compares the game trajectories with the ones that came out of my ballistics calculator, the other two graphs show only the game ballistics.  (Whoops, just found out that this is a bit out of date.  5.56 is much closer to the "real M16" curve than that spreadsheet suggests.)

The included ACOG reticles are realistically proportioned, with accurate 7 degree fields of view.  These are the actual scopes the Army uses, and the ones BIS modeled on the guns in ArmA.

http://files.filefront.com/NWD+Ballisticsrar/;8156001;;/fileinfo.html