The bullet trajectory is relatively flat out to 300 meters, at which point it starts to drop. True bullet trajectory is an arch.
For example, based on a 6.5x55mm 140 gr cartridge, with a 300 meter zero, the point of impact is roughly 8 inches ABOVE point of aim at 200 meters. (with a 5.56 round its roughly 5 inches, and a .308 is roughly 6)
These bullet physics completely render the reticle on the ARCO useless, as the chevron is designed to give 100 & 200 yard references on the BDC, as well.
Zero distance should also effect your POA/POI.
For example, with a 200m zero, same cartridge, a shot at 100 meters would only be roughly an 2-2.4 inches higher than point of aim. While a shot at 300m would be roughly 9 inches lower than point of aim.
Please incorporate true ballistics trajectory into the engine/game physics.
UPDATE!
Upon further testing there does seem to be some slight POI shift with Sub-300m shots. However, this shift is negligible, and is even more negligible at 100 meters when compared to 200 with the same zero. I have described above how this effects proper use of the ARCO reticle. Please see the picture at this link for the POI/POA for the AGOC/ARCO Chevron reticle: http://pro-patria.us/yahoo_site_admin/assets/images/ACOGReticle.243183548_large.jpg