[JaM]

Discusion on Yahoo board is quite big. Accuracy system works great until 1970, after this date new ammunitions are avaiable and this should be taken into account. I know that most of datas are classified, so you need a formula that will work for all tanks with data avaiable. My sugesstion is use L/D ratio of APFSDS projectiles as measurment for accuracy and degree of technology of tank gun. Soviet tank guns were quite unaccurate at ranges over 1600m,they used APFSDS rounds with L/D ratio 10:1 - 13:1,newest projectiles has better accuracy (BM-42,BM-42M etc...)guns that fires them are upgraded so they can fire longer rounds with better L/D (20:1, autoloader prevents to use longer rounds such as US M829A2 or A3 with L/D 30:1 - 37:1).Western tanks started with L/D 10:1 (M735) but they develop better ammo quite soon as M774(not so sure but it is in L/D 15:1 - 20:1 region) M833 (L/D around 20:1) or M900 (L/D 30:1).
Im not suggesting use L/D value as a acc value, but just better variable than lenght of gun.Soviet HEAT ammo for example are stated as more accurate as APFSDS rounds (0,2mil dispersion for HEAT-FS and 0,25-0,3mil for APFSDS)