Field guns die modifiers

[dirk]

In the introduction of Infantry Attack 1.0 (Second addition rules)
Artillery: Large guns that provide long-range fire support. In Infantry Attacks games artillery is not present on the game board (the artillery pieces in the game are termed "field guns"), but instead represented by "increments" that can bombard(9.0).
Along with the statement of 8.3 Fire Values:
A units fire value and range are printed on its playing piece..... Some units have fire values printed in outline white. This dates from an earlier edition of these rules and you may ignore the distinction.
Rule 10.0 Direct Fire:
Activated units withe Direct Fire Values (including field guns) may fire on hexes within range to which they can trace LOS. 

I take this to mean that any artillery piece, on the board are field guns and uses the Direct Fire table to resolve combat.
This differs from Panzer Grenadier rules.

Of course this may change with future games in the special rule sections.