Originally, it was posted in General discussion (link), but I see no response there, so I'll repost info here.

1) stock iron sights visually is not centered as shown on a screenshot
2) stock iron sight physically is not centered and rifle shot lower than the tip of the iron sights pin (shots fired can be seen on photo below, on the right from the iron sight)



3) F2000 in game does not have an option for underbarrel attachments, as it should
- it uses the same grenade launcher that is present in game already - the one, that TAR-21 uses (lightweight 40 mm underslung GL1 grenade launcher, mounted instead of a plastic part, see photo below)
- also, there is a "tactical" variant of rifle, that also can be used with handles that mount on the front (as it can be seen on photo below) or by dismounting front lower part, under which there's a rail system





4) there's no possibility to use alternate backup sights, as it should be (not really a problem, if stock sights could be fixed)