British Light Anti-Aircraft Guns – 20mm

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Although the British considered 20mm AA guns a second class weapon – preferring the 40mm Bofors - they manufactured and deployed a lot of 20mm guns.

Currently in SP, the only 20mm AA guns available in the British OOB are on the Crusader Mk I SPAAA.

ANZAC have a towed 20mm AA Gun (unit 153) available for the entire war.
Canada has a 20mm quad truck (unit 109).

Perhaps the following units could be considered for the British OOB:

• Towed 20mm AA
• Truck mount 20mm AA
• Airborne towed 20mm AA


Don, If you can use the following information then great. If not, I enjoyed the research, and perhaps some people may find it interesting.



I have sources and/or photos for British 20mm AA units that include:

1. Oerlikon 20mm single AA towed....................... 1940 – 1946

2. Breda 20mm single AA captured towed............
3. Breda 20mm single AA captured truck mount........ Sep 1941

4. Polsten 20mm single AA towed .................... Mar 1944 - 1946
5. Polsten 20mm triple AA towed.......................
6. Polsten 20mm quad AA towed...................... Mar 1944 - 1946

7. Polsten 20mm single AA truck mount.............. Mar 1944 - Jul 1944
8. Polsten 20mm twin AA truck mount.................. Mar 1944 - 1946
9. Polsten 20mm triple AA truck mount................. Mar 1944 - 1946
10. Polsten 20mm quad AA truck mount.............. Mar 1944 - 1946

11. Hispano 20mm single AA Airborne towed......... May 1943 - Mar 1944
12. Polsten 20mm single AA Airborne towed ........ Apr 1944 - Jan 1945.

Polsten Manufacting

The British started manufacturing Polsten guns in Nov 1943, but may not have entered service until Mar 1944.

Britain produced 13,588 Polsten guns in 1944.

300 Polsten airborne mountings were made in 1943.

http://www.wwiiequipment.com/index.p...raft&Itemid=58

Airborne 20mm AA guns

Info on airborne 20mm and deployment:

On 22nd May 1943, 2nd Airlanding Light Anti-Aircraft Battery R.A. (T.A.) was formed. To provide anti-aircraft defence to 6th Airborne Division.

The Battery was equipped with 18 x 40mm Bofors AA guns and 48 x 20mm Hispanio Suiza AA guns.

From Jan 1944 the Battery carried out extensive training being allocated seven Horsa gliders to carry 40mm gun detachments and the Battery Headquarters.

carried out live firing with both the 20mm and 40mm AA Guns. The Battery continued training into the next month and on 30th March 1944 received the new Polsten 20mm AA Gun to replace the 20mm Hispanio AA Gun. On the same day 1 officer and 46 Other ranks were detailed for specialised training in the use of enemy equipments.

On D-Day, the Battery provided a detachment in support of 6th Airborne Division. The Detachment remained with the Division throughout the campaign in Normandy, returning to the UK on 30th August 1944.

On 1st September 1944 the rest of the Battery prepared to support the 1st British Airborne Corps and 1st Airborne Division in Operation Market Garden. The Battery provided anti-aircraft defence for an airstrip near Grave and for the 1st British Airborne Corps HQ at Nijmagen.

On 17th September, enemy tanks cut the road East of Veghel. Guns deployed in an anti-tank role.

24th January 1945. The Battery was disbanded.http://www.gotoitgunners.co.uk/twoairlanding.html

I also have four 20mm shell casings dug up on the battlefield at Arnhem by Hans van der Velden near the Hartenstein Hotel where the British 1st Airborne Division made its heroic stand. These came from the Recce Squadron's second gun which survived to the end of the battle.http://bcoy1cpb.pacdat.net/20_mm_aa_guns.htm



From a British Airborne war diary Sept 1944:

1000 - Reports that the enemy have crossed the river LEK in force at RENKUM 6276 and is pressing east. Capt. Costeloe and Lieut. Christie site Polsten section to cover the road west.
1645 - Polsten sections leave to support A and D Troops who are under strong pressure from the enemy. Section fire on their objective. Lieut Christie killed whilst attempting to save Jeep and Polsten. www.pegasusarchive.org/arnhem/war_recce.htm

1st Airborne Reconnaissance Sqn

In accordance with ' Recce policy ' ; the fire power of the jeeps was substantially upgraded. Every jeep had a Vickers "K" .303 machine gun mounted with a round magazine holding 96 rounds. In addition some had 2 20mm polsten cannons towed behind the jeep. The Polsten cannons were an Anti Aircraft gun but, due to their high firing rate, they were a very effective ground weapon. They also carried standard infantry weapons including two 3" mortars and 2" mortars, a Bren Light machine gun, standard rifles but with sniper sights, a Piat gun and many and various hand grenades. Most men had a Sten gun and the Radio Operators a revolver.http://www.justordinarymen.org.uk/pa...202780890.html

British Army use of 20mm AA guns

The use of light anti-aircraft guns in the British Army is particularly difficult to gauge. A 1944 Infantry Division is quoted at 71 guns, but few of its sub-units own up to having fielded them. This would appear to be due to the fact that the 20 mm gun was issued on a much lower scale than originally planned. Rather than being deployed throughout the Division they were maintained solely by the Light Anti Aircraft Regiment instead, along with its 40 mm Bofors guns. However, the 20 mm did survive in the Armoured Regiments, at least until August 1944.

The original British defence was a mounting which held twin Bren light machine guns, each fitted with a 100 round drum magazine and fired from either a tripod or the rear of a 15 cwt truck. The Polsten did not appear until early 1944 and as such was available for the campaign in the West. It was derived from the Swiss 20 mm Oerlikon which had debuted some 30 years earlier. A team of Polish designers were working on a lightened, simplified version when the Germans invaded their homeland. The team were able to reach Britain and continue the project, which was christened Polsten in honour of Poland and the Sten factory, who manufactured the weapon.

The Polsten could be deployed as a vehicle weapon or on a towed carriage, which weighed approximately 500 kg. It served alongside the Oerlikon which inspired it, the original weighing in at around 67 kg for the gun alone and having a slightly higher rate of fire (465 to 480 rpm) by comparison. The Oerlikon could be fed by either a 60 round drum or a 20 round box. Both weapons could be found on the Anti Aircraft machines of an Armoured Regiment or Armoured Car Regiment and used the same ammunition.

The British also used the American Hispano-Suiza 20 mm which had higher rate of fire of some 650 rpm, but I've no other data for this weapon. http://www.bayonetstrength.150m.com/...ft_weapons.htm

Light Anti-aircraft Regiment - with fifty four towed 40-mm light anti-aircraft guns, divided into three Batteries, with three Troops of six guns per Battery. Additionally, each Battery was reinforced by one Troop of eight truck mounted 20-mm light anti-aircraft guns for the early part of Normandy campaign. These Troops were subsequently disbanded during July 1944, and were not implemented in Italy.

(I have a photo of a single towed Oerlikon being used in Italy Oct 1944)
…
In mid 1943 the previous Machine Gun Battalions began to be replaced by Support Battalions. A Support Battalion had one Brigade Support Group per Infantry Brigade in the Division.
Each Brigade Support Group had three Companies. The first had twelve Vickers medium machine guns in three Platoons of four guns each. The second had eight 4.2-in mortars in two Platoons of four weapons each. The third had sixteen 20-mm light anti-aircraft guns in four Platoons of four guns each.

Support Battalions operated with several Divisions in Italy, where the 20-mm light anti-aircraft guns were largely dispensed with. In February 1944 the Machine Gun Battalion (as described above) was reintroduced, mixing Vickers MMGs and 4.2-in mortars, and it was this organisation that was used throughout in Northwest Europe. All the Support Battalions in Italy had converted to the Machine Gun Battalion organisation by the end of July 1944. http://www.bayonetstrength.150m.com/...0to%201945.htm

Photo of CMP 20 mm AA trucks on the beach in Normandy in July 1944. They appear to be British 7th Armoured Division.
http://bcoy1cpb.pacdat.net/20_mm_aa_guns.htm

Captured Italian Breda 20mm AA guns

6 Light AA Battery was issued with captured Breda 20mm single AA guns, used to protect road convoys and trains.
http://coleraine-battery.tripod.com/page19089.htm

Info on the captured Breda:
http://www.ian.a.paterson.btinternet...lery.htm#Breda

Here are British armoured cars with the Breda 20mm fitted:
http://www.desertrats.org.btinternet...erringtons.jpg

Against ground targets the gun fired armour-piercing rounds, while aircraft targets were engaged with a high explosive projectile that incorporated a very sensitive percussion fuse to operate against light aircraft structures. The latter projectile also had a self-destruct feature if it did not hit a target. The tripod platform of the gun provided a steady base for firing and against aircraft the gun proved very successful. Against tanks it was less effective, but any weapons captured by the Allies during the North African campaigns were usually mounted on the light armoured cars to provide them with more offensive capability than a machine gun provided and Portee to provide mobile air defence for armoured columns.

The Long Range Desert Group also mounted them on the rear of some it is vehicles nicknaming them 'Scorpions' as they then had a sting in their tail.http://www.btinternet.com/~ian.a.pat...partillery.htm


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