[zastava128]

OK, last batch of suggestions. I think I've gone through pretty much all the relevant literature now.

Artillery and brigade support weapons – from 5/41 on

I’m afraid there’s – as far as I know – no literature on the subject in English, so my sources are:

Nikola Anić: Narodnooslobodilačka vojska Jugoslavije (Belgrade 1982, in Serbo-Croatian only)
Miloš Pajević: Artiljerija u NOR (Belgrade 1970, in Serbo-Croatian only)

The formations, especially before 1945, had incredible variety. I have tried to streamline them as much as possible for the sake of playability.
First I’ll list the weaponry used, then I’ll list the organizational structure, roughly divided into four time periods.


Weaponry

The weapons are listed by type, followed by a nation tag in brackets: YU – ex-Royal Yugoslav Army, IT – Italian captured, GE – German captured, USSR – Soviet aid, USA/UK – American or British aid, respectively. Bear in mind the designations are the local ones.

Note that the partisans abandoned the “80mm” designation for 76.5mm guns, and simply used “76mm” instead.

65mm mountain gun (YU) refers to unit 21 in this (Yugoslav) OOB
Date: 11/42-12/44

65mm mountain gun (IT) refers to unit 320/593 in spob34
Date: 11/42-12/44

75mm mountain gun (IT) refers to unit 324/325/595 in spob34
Date: 11/42-12/46

75mm mountain gun (GE) refers to unit 489 in spob16
Date: 1/45-12/46

76mm mountain gun (USSR) refers to unit 51 in spob11
Date: 1/45-12/46. Suggest radio code 2.

76mm field gun (YU) refers to unit 133 in this OOB (to keep things simpler)
Date: 11/42-12/46

76mm field gun (USSR) refers to unit 282 in spob11
Date: 1/45-12/46. Suggest radio code 2.

75mm pack howitzer (USA) refers to unit 165 in this OOB – after it is replaced according to Michal’s suggestions
Date: no changes from current OOB

75mm howitzer (YU) refers to unit 54 in this OOB
Date: 11/42-12/44

75mm howitzer (GE) refers to unit 152 in this OOB
Date: no changes from current OOB

100mm howitzer (YU) refers to unit 147 in this OOB (it was more common than the M.28, and to keep things simpler)
Date: 11/42-12/46

100mm howitzer (IT) refers to unit 31 in spob34
Date: 10/43-12/46. Suggest radio code 1.

105mm howitzer (YU) refers to unit 148 in this OOB
Date: 1/45-12/46. Suggest radio code 1.

105mm howitzer (GE) refers to unit 132 in spob16
Date: 1/45-12/46. Suggest radio code 1.

105mm howitzer (USA) refers to unit 164 in spob12
Date: 4/45-12/46

122mm howitzer (USSR) refers to the unit Michal mentioned above.
Date: no changes from current OOB

150mm howitzer (GE) refers to unit 151 in spob16
Date: 10/43-12/46. Suggest radio code 1.

152mm howitzer (GE) refers to unit 318 in spob16
Date: 10/43-12/46. Suggest radio code 1.

2pdr AT gun (UK) refers to unit 59 in spob07
Date: 1/45-12/45 (were used since 11/43, but only as coastal defense before 1945). Suggest radio code 1.

6pdr AT gun (UK) refers to unit 60 in spob07
Date: 9/44-12/46

25mm AA gun (USSR) refers to unit 347 in spob11
Date: 1/45-12/46

20mm AA gun (UK) refers to unit 749 in spob07
Date: 1/45-12/46

37mm AA gun (USSR) refers to unit 57 in this OOB
Date: no changes from current OOB

This also means the following guns that are in the current OOB were actually never used and should be removed:
unit 20 76L51 AT-Gun
unit 55/66 76.2mm L51 obr36 gun
unit 68 152mm FH

The other guns and respective formations (e.g. 37mm inf gun, various AT guns) that appear in the OOB don’t need any changes, except that the start date of the 7.5cm PaK (unit 24) should probably be 1/45, not 1/44.


Organization of Artillery

5/41-10/42

This period is mostly covered OK (there were just 37mm inf gun platoons and the odd AT gun).
Occasionally the partisans used some larger captured guns, but this was incredibly rare. I think the “captured” feature can simply be used to represent the few guns they did have (a dozen or so 65mm and 75mm mountain guns plus the odd 100mm howitzer).

11/42-9/43

This period saw the first true artillery units formed.
Each partisan brigade (in this period usually 1000 men divided into 4 battalions - so basically a partisan brigade was only equivalent to a battalion in a regular army) had:

-a single 45mm AT gun (from 5/43 rarely replaced by German 5cm PaK)
-2x light (usually Brixia) Mortars
-4x 81mm mortars
-8x MMG/HMGs

All these weapons are already in the Yugoslav OOB, I’m just listing this for a possible “brigade support weapons” formation.

A Division of partisans (usually 3 brigades) could have any or all of the following batteries (most, however, had only one):

-Mountain gun battery: 3x 65mm (IT, YU) or 3x 75mm (IT)
-Lt. Howitzer battery: 3x 75mm (YU, from 5/43 GE)
-Med. Howitzer battery 2: 2x 100mm (YU), sometimes with an extra 76mm field gun (YU)

A Partisan Corps could have one of the following:
-A Med. Howitzer battalion: 3x 100mm howitzer battery, each with 2 guns (YU)
-A Lt. Howitzer battalion: 3x 75mm howitzer battery, each with 3 guns (YU, from 5/43 GE)

10/43-12/44

Italian surrender meant a significant increase in available guns, and the British gave some artillery as aid.

Each partisan brigade had (on average):
-2x 45mm AT guns (rarely replaced by German 5cm PaK)
-4x light (usually Brixia) Mortars
-8x 81mm mortars
-8x MMG/HMGs
-2x 65mm mountain guns (YU, IT) or 75mm mountain guns (IT).

These are already implemented in the current OOB; again this is for a potential “brigade support weapons” formation.

A Division of partisans could have an artillery battalion consisting of the following, but in reality only the best divisions had a full-strength battalion:

-1x Mountain gun battery: 4x 65mm (IT, YU) or 4x 75mm (IT)
-1x Field Gun battery: 4x 76mm (YU)
-1x Howitzer battery: 4x75mm (YU, GE) or 4x 100mm (YU, IT) or 4x150mm (GE)

A Partisan Corps could have one or both of the following:
-A Med. Howitzer battalion: 3x 100mm howitzer battery, each with 2 guns (YU). Sometimes an additional, lone 152mm howitzer (GE) would be attached to the battalion.
-A Lt. Howitzer battalion: 3x 75mm howitzer battery, each with 3 guns (YU, GE)

A few units were equipped and trained by the British:
From 3/44, one infantry division had a battalion of 3 batteries, each with 4x 75mm pack howitzer (USA).

There were two motorized arty battalions deployed in 9/44 and 11/44. They had:
-2 batteries, each with 4x 75mm pack howitzer (USA).
-1 battery with 4x 6pdr AT guns (UK).

In 1945 both of these were incorporated into the artillery brigades.

In this period the partisans also got their hands on some MGCA M.37 Breda (AAMGs, see the Italian OOB). They were organized into platoons of 3.

1/45-12/46

The partisans grew into a regular army. By this time, a division had 10000 men. There was a massive influx of Soviet equipment, and most artillery was of their origin.

IMPORTANT: All of the following equipment is Soviet unless noted otherwise.

An infantry brigade (still 4 battalions, but now the battalions had a lot more men) had as support:
-2x platoons of 3x 45mm AT guns each
-a single platoon of 6x 12.7mm DShK AAMGs (these will need to be added to the OOB)
-3x platoons of 6x 82mm mortars each
-4x platoons of 6x 50mm mortars each
-3x platoons of 6x MMG/HMGs each
-4x 76mm field guns

Each infantry division at full strength would have an artillery brigade supporting it. The most common configuration was (note that sometimes captured equipment was used instead – if you wish to simplify you could just ignore most or all of the captured equipment):

1. battalion: 2 batteries, each with 4x 45mm AT guns. (very rarely with 57mm AT guns)
-sometimes replaced with 50 or 75mm PaK guns (GE), or 2pdr/6pdr guns (UK)

2. battalion: 3 batteries, each with 4x 76mm field gun or 4x 76mm mountain gun.
-sometimes replaced with 75mm mountain guns (IT, GE), 76mm field guns (YU), or 75mm pack howitzers (USA).

3. battalion: 3 batteries, each with 4x 120mm mortar.

4. heavy battalion: 2 batteries, each with 4x 76mm field gun plus 1 battery with 4x 122mm howitzer.
-sometimes replaced with 100mm howitzers (YU, IT), 105mm howitzers (YU, GE) or 150mm howitzers (GE). From 4/45, 105mm howitzers (USA) were also used.

5. AA battalion: 3 batteries, each with 4x 25mm AA gun

Occasionally there was an independent battery of 2x 152mm howitzers (GE) available.

There were independent batteries of 6x 37mm AA guns (USSR) or 20mm AA guns (UK).

From 3/45 captured German 8.8cm FlaKs were available, organized into independent batteries of 2 guns, with transport. Used as AT guns.