[Gun and Ammo Type modifications are distinct from all others because they modify the Basic TH# - not the To Hit DR - to achieve the Modified TH#. The distinction is very important and care should be taken not to lump these modifications together with a DRM.]
4.1 BARREL LENGTH: Put simply, the longer the gun barrel (or tube), the more accurate a weapon is at greater ranges. Therefore, all Guns are rated for tube length as being either short (*), normal (no suffix), long (L), or extra long (LL). Normal length tubes have no effect on the Basic TH# of that Gun, but all other types are subject to modification of their Basic TH# when firing at a range > 12 hexes. Barrel Length does not affect any resulting To Kill DR; the added lethality of the longer tubes is built into the To Kill Tables. Q&A
4.11 *: Short barreled Guns must subtract one from their Basic TH# when firing at a range > 12 hexes.
4.12 L: Long barreled Guns must add one to their Basic TH# when firing at a range > 12 hexes.
4.13 LL: Extra long barreled Guns must add one to their Basic TH# when firing at a range > 12 hexes, or must add two to their Basic TH# when firing at a range > 24 hexes.
4.2 SMALL CALIBERS: Smaller shells generally lost velocity faster than larger shells, affecting trajectory, stability, and ultimately, accuracy. Any weapon (including MG) ≤ 57mm is subject to a -1 modification to its Basic TH# for every 12 hexes (or fraction thereof) beyond 12 hex range. A weapon ≤ 40mm is subject to an additional -1 modification to its Basic TH# at > 12 hex range. Q&A
4.3 APCR/
4.4 SMOKE: A Gun firing SMOKE at ≤ 12 hexes must add two to its Basic TH#.Q&A
4.5 MODIFIED TH#: All Gun & Ammo Type modifications are cumulative and transform the BASIC TH# to a MODIFIED TH#. All other factors affecting the To Hit process are DRM which affect the To Hit DR, not the TH#.
EX: A German 4.2cm Ie PaK 41 (40LL) firing APCR at a tank 25 hexes away has a Basic TH# of 6, but a Modified TH# of 3 (+2 [LL] -2 [APCR] -2 [≤ 57mm] -1 [≤ 40mm] = -3).