[Mobhack]

Ran a quick test and bought those guns in 47.

Entirely plottable for HE or Smoke as long as the target hex was beyond minimum range.

If the target was inside minimum range, then these 2 ammo types were not plottable - and in that case the red Cancel button is "auto-pressed" as a reminder to the user that the gun cannot reach that hex. Same happens if outside max range (tested with 82mm mortars).

It has been a while since I had an artillery piece drift into min our out of max range that I wanted to cancel right then, but I think in that case one has to adjust it to a legal target hex, then press cancel - or just let it fire till its mission is concluded. That is the way the original SSI designers coded this - not an addition by SPCamo, AFAIR.

You can easily test this by starting a battle in the battle generator as an advance (so you can lot arty as pre-game bombardment with no waiting) and buying the zis platoon and a mortar platoon. Try plotting the zis guns a few hexes away - the red button will remain down. Advance the target hex further away and it will eventually clear and allow plotting, The mortars will have a shorter minimum indirect range, and at 70 odds hexes max range they will also put the red button down as at maximum range. The zis field guns max range is beyond the map size. Once done testing, then exit the battle.