General idea:
the range of a artillerie-gun is not alone determined by it´s caliber, but by the propulsion-charge in relation to the caliber.
ww I and II both made exesive use of artillerie and it was a constant struggle to build a gun that would outrange the enemy guns.
This is the list with real ranges and estimated hex ranges(roughly 4km->1 hex). Implementing this change is a matter of minutes. Dealing with the balance issues/changes this will cause is a different matter.
The same needs to be done with ship guns as well of course, but i am not touching mayor naval changes before pacific is out. i hate doing stuff more than once.

Let me know what u think about this. If u have any different infos on a gun, please let me know.
ingame-name: Real: Hex:
StuGIVATY 2 km 1
75mmFK16nA 12.3 km 3
105mmleFH18 12 km 3
15cmsFH18 12.3 km/Rap 18.2km 3/4
17cmK18 29.6 km 7
21cmMrs18 16.7 km 4
15cmNW41 10 km 2
21cmNW42 8 km 2
30cmNW42 4.5 km 1
15/30cm RW 56 4.5/8 km 1/2
Wurfrahmen40 8 km 2
Panzerwerfer42 10 km 2
StuGIIIB 2 km 1
StuH42ATY 5.4 km 1
Brummbär 4 km 1
Sturmtiger 5 km 1
SturmpanzerI 4 km 1
sIG33IISf 4 km 1
sIG38tM 4 km 1
Wespe 12 km 3
Hummel 13,3 km 3
KarlGerat040 4-11km 1-3
Gustav 28-47km 7-14
280mmK5 62/86RAP 15/21
V1ATY ----- ----
V2ATY ----- ----
KV2ATY 12.4 km 3
SU152ATY 17.23 km 4
ISU122ATY 19.8 km 5
76mmM1939 13 km 3
76mmM1942ATY 13.2 km 3
122mmM1938 11.8 km 3
152mmM1938 12.4 km 3
203mmM1931 16 km 4
SU5_2 8.8km 2
SPT_18 ----- ----
BT7A-ATY 4.2 km 1
SU76ATY 13.2 km 3
SU122ATY 11.8 km 3
ISU152ATY 17.2 km 4
BM8_8 3-12 km 1-3
BM8_24 3-12 km 1-3
BM13Katyusha 3-12 km 1-3
BM31Katyusha 3-12 km 1-3
FireflyTulip 1 km 1
QF25pdrATY 12.3 km 3
BL5-5inch 16.6 km 4
BL6inch26cwt 10 km 3
BL7-2inch 17.9 km 4
76mmLandMattress 7.2 km 2
Bishop 12.3 km 3
GBM7Priest 10.9 km 3
Sexton 12.3 km 3
CruiserCS 1.8 km 1
CrusaderCS 1.8 km 1
CromwellCS 1.8 km 1
ChurchillAVRE 2.4 km 1
M3-75GMC-ATY 12.7 km 3
75mmM1A1 8.8 km 2
105mmM2A1 11 km 3
155mmLongTom 23.7 km 6
M7 10.9 km 3
75mmHMCM8 7.6 km 2
155mmM12GMC 19.5 km 5
M4A3-105ATY 11.2 km 3
8InchM1 32 km 8
Calliope 3.7 km 1
Xylophone 3.7 km 1
JB2Loon ----- ----
75mm75-18 9.5 km 2
75mm75-27 9.8 km 2
75-32M37ATY 12.5 km 3
100mm100-17 20 km 5
105mm105-28 11 km 3
149mm149-19 14.2 3
M40da75-18ATY 9.5 km 2
M43da105-25ATY 2.5 km 1
ITBrummbar 4 km 1
FR75mmmle1897 11 km 3
FR105mmmle1913 12 km 3
FR155mmCmle1917 11.2 km 3
75mmwz97 12.7 km 3
105mmwz29 15.5 km 4
155mmwz17 10 km 3
SK75mmvz15 8.2 km 2
SK100mmSkodavz14-19 8.4 km 2
SK150mmvz25 14.6 3
HU80mm18M 5 km 1
HU105mm37M 11 km 3
HU150mmBofors ----- ----
HU15cmNebelwerfer41 10 km 2
RO75mmmodel1897 11 km 3
RO105mmmodel1913 12 km 3
RO150mmmodel1934 15 km 4
BG75mmM1904 8 km 2
BG105mmM1935 11 km 3
BG12cmM1909 8 km 2
YU75mmM15 8.2 km 2
YU105mmM13 12 km 3
YU155mmM17 19.5 km 5
GR75mmM1919 11 km 3
GR105mmM1925-27 11 km 3
GR155mmM1917 19.5 km 5
NO75mmm-01 10 km 3
NL75mmKrupp 6 km 2
NL105mmBofors 16.5 km 4
NL150mmKrupp 12.3 km/Rap 18.2km 3/4
BECanonde75mle 11 km 3
BE105mmleFH16 9.2 km 2
BEObusierde155 6.8 km 2
15cmsIG33 4 km 1
76mmM1943 4.2 km 1
SU76MATY 13.2 km 3
A10CruiserCS 5.4 km 1
M42da149-40ATY 23.7 km 6
76mmM1902-30 13.2 km 3
CZ75mmvz15 8 km 2
CZ100mmSkodavz14-19 8.4 km 2
CZ150mmvz25 23.8 km 6
70mmSchneiderM08 7 km 2
75mmSchneiderM06 8.5 km 2
105mmVickersM22 11 km 3
122mm M10-30 7-9 km 2
152mmM10-30 9.8 km 3
QF18pdrATY 6-10 km 2-3
BL4-5inch 18.7 km 4
Grille17 29.6 km 7
Grille21 16.7 km 4
HeuschreckeATY 12.3 km 3
sers,
Thomas