Finnish (OOB 35) corrections and suggestions:
All weapons which fired the Long Solothurn cartridge (i.e. 20 x 138B) should have the same armor penetration. Those would be weapons 005, 006, 010, 133, 177. The differences of muzzle velocities between weapons were small and all AP ammo regardless of user was based on the same Solothurn (i.e. Rheinmetall) designs. The "correct" AP Pen is a matter of taste and source; I would say 4.
The same inconsistency appears in other countries which used the same ammunition in AA, AT and tank guns, most notably Germany and Italy. The only significant historical variation was APCR ammo, which was available only for German tank guns.
Weapon 006 20mm M/40 VKT was a twin barrel gun, so HE kill should be 1.5x10 = 15
Weapon 014 37mm M36 L37: according to Finnish test AP penetration at muzzle should probably be 6. Source:
http://www.jaegerplatoon.net/AT_GUNS1.htm#37PstK36
(the difference in barrel length is probably due to different way of measuring, i.e. L/37 is without muzzle brake)
Weapons 023 & 024: AP penetration in Italian OOB is 6, which is also consistent with the data found here
http://www.jaegerplatoon.net/AT_GUNS2.htm#47PstK.
Weapon 033 75mm K 17 FG: real max range was 10,700 meters, so Weapon Range 201. AP ammunition was available since Nov. 1943, penetration 9.
Weapon 024 76mm M 27 FG: AP Pen 6 with Finnish AP-T (since Dec 1942), HEAT (German HEAT design) available since July 1944 with penetration 9.
Weapon 036 76mm K 02 FG: Real max range 10,600 meters, so Weapon Range 201. AP Pen 10 with Finnish AP-T (available since Dec 1942). Max. range with pre-WW2 ammunition only 7,900 meters (158) (i.e. off-map artillery units with this gun should not be available before 1939 or so).
Weapon 049 76mm M 02 FG: T-28 tank gun L-10, should be replaced by Soviet (OOB11) weapon 049 76.2mm L10 L/26
Weapon 055 75mm M97 L36: Finnish AP-T (75 psa - Vj4) with penetration 9 could be added as "Sabot". Range of course the same as normal. Firing this ammunition was for emergency use only (i.e. if HEAT didn't do the job), since repeated firings would break the carriage, but nevertheless it was available.
Weapon 070 122mm H 09-30: Correct Finnish designation should be 122mm H 09-40. The Soviet 09-30 was also used, and had similar performance, but the 09-40 was more common. Max. range was only 8,500 meters (170), so no off-map units with these howitzers should exist. Oh dear. You will probably have to add a new weapon with correct max. range and keep the old one for compatibility with old scenarios.
Suggestion: add original 122mm H 09, range 7,600 meters (152). It should replace Weapon 070 in all artillery units before 01/041, except of course in the off-map units which shouldn't exist.
Weapon 071 105mm H 37 FH: max. range 12,500 meters, so Weapon Range 203.
Weapon 074 122mm H 38 FH: max. range 11,800 meters, so Weapon Range 202.
Weapon 079 150mm H 40 FH: max. range 13,000 meters, so Weapon Range 203 (this was German 15 cm sFH 18). APHE available since August 1942, penetration unknown (theoretically estimated probably around 13). HEAT since August 1944, penetration 19 in German OOB.
Weapon 080 152mm H 09-30: max. range only 9,500 meters, whether that qualifies as range Weapon Range 200 and off-map use or not is up to you. No HEAT in Finnish service, APHE available, estimated penetration 9.
Weapon 102 114mm MkII: max. range only 7,500 meters (150). Original British designation Q.F. 4.5 inch Howitzer Mk 2. Finnish designation was 114 H 18, so name should probably be 114mm H 18 FH
Weapon 103 203mm H 17 Hwtz: max. range only 11,200 meters (201). (The range given by the
http://www.jaegerplatoon.net/ARTILLERY7.htm is even less, but probably the British sources are more reliable on this one.)
Weapon 110 152mm H 37 FH: no heat in Finnish service, APHE with penetration 15 (extrapolated from 124mm at 1000 meters). Soviet ML-20. The assault gun version of this gun-howitzer has a rather low penetration (13) in both the Finnish and Soviet OOBs.
Weapon 099 Chauchat M1915: suggest reducing HE kill to 4 due to very low cyclic rate of fire (250 rpm) and small magazine.
Weapon 113 BAR: not actually the BAR but a further FN development in 7.92x57 mm with a quick change barrel and selectable rate of fire called FN D (i.e. could be called 7.92mm FN D LMG)
Weapon 133 20mm Lahti ATR: had adjustable sights to 1,400 meters and was often used at 1000+ m ranges against soft targets and such, so range 14 is clearly too low.
Weapon 139 Maxim M/31 AAMG: as far as I can tell, this is supposed to represent the M/31 VKT AAMG designed by Aimo Lahti. The M/31 was a double barrel gun with a cyclic ROF of 900 rpm per barrel (1800 total). That would be about HE Kill 8, so the gun should have HE Kill 1.5x8 = 12. Should probably be named to M/31 VKT AAMG.
Weapon 144 Maxim M/40 AAMG: this is supposed to be the improved M/31-40 VKT AAMG. There were no differences to the M/31 above which could be modelled at the "Weapon" level. In fact it is identical to the M/31 in the current OOB as well, so I don't know why anyone has bothered to enter it.
Weapon 228 105mm K 29 FG: max. range 14,400 meters (204).
Weapon 230 105mm H 33 FG: (10,5 cm leFH 18) max. range 202 in German OOB. Finnish sources say 11,300 meters, but such small differences are common with artillery pieces. HEAT penetration 10 (as German OOB). HEAT available since May 1944.
Weapon 231 155mm Schneider: max. range about 11,000 meters (201) by most sources. Finnish designation was 155 H 17, so name should probably be 155mm H 17 FH
Weapon 248 76mm LK 13 FG: max. range 7,000 meters (140). AP and HEAT ammunition as Weapon 024.
Weapon 249 76mm K 36 FG: max. range 13,600 meters (204). Penetration 12 with Finnish AP (since Dec 1942). 8 with German HEAT (since July 1944).
Suggestions:
Add 120mm K 78 FG (Materiel de 120 Long, Mle 1878). Range 12,400 meters (202), HE Kill whatever 120mm guns get (14 or 15?). Only HE ammo. Corresponding units should have ROF 3 due to lack of recoil mechanism (actual rate of fire was even lower, but most WW1 vintage field artillery pieces have a highly optimistic ROF in SPWW2, even the ones with a recoil buffer). Available since April 1940.
Add 155mm K 77 FG (Canon de 155 Long, Mle 1877). Range 12,300 meters (202), standard HE Kill, HE only, ROF 2 (rigid carriage). Available since Jan 1941.
Add Quad Maxim AAMG from Soviet OOB (weapon 115). A large number of these guns were captured already in Winter War and used on top of trucks similar to the Soviet usage. Available Jan 1941. I would like to point out that the Soviet OOB weapon does not follow the rule that Quad Guns should have 1.875x HE Kill of single weapon (1.875 x 5 would be only 9, but the weapon has HE Kill 11). I don't think it's a good rule, to be honest, since it makes triple and quad barrel weapons quite weak, but that's what the Mobhack Guide says.
Add Chauchat M1915 AAMG. The Chauchat was replaced by captured DP LMGs as infantry LMG during the Continuation War, but artillery and 2nd line units used them as AAMGs, since they came with AA sights from France and Finland was not exactly swimming in AA weapons. Available April 1940.
Sources: mostly Jaeger Platoon web site
http://www.jaegerplatoon.net/MAIN.html, some Wikipedia.