The Polsten 20mm AA Guns at Operation Market-Garden - 1944

A relatively unique, and as a result obscure, weapon existed within the TO&E of the 1^st Airborne Reconnaissance Squadron at Arnhem. The weapon was the Polsten 20mm Anti-Aircraft Gun, No.2 Mk II. There were two guns forming a Section, each being towed behind one of the squadron’s jeeps. Primarily designed for limited air defense, their high rate of fire proved them to be a very effective ground weapon. Both the gun and jeep could be carried by a single Horsa glider.

The Polsten 20mm Anti-Aircraft Gun stowed inside an
Airspeed AS 51 Horsa Assault Glider; would probably
have jeep stowed with it in an operational flight

Although not the best of images the following is the official loading diagram for a Polsten 20mm AA Gun, along with a jeep, trailer and motorcycle, in a Airspeed AS51 Horsa Assault Glider Mk I.

Although taken later during Operation 'Varsity' in March1945
 this shows a Jeep and Polsten 20mm AA gun off-loading from
 a Horsa glider

Their presence is corroborated in the Air Load Manifest Operation MARKET - First Lift. See; http://arnhemjim.blogspot.com/2012/06/hamilcar-gliders-at-operation-market.html. Copies of the manifest are listed towards the end of the page.

The airborne configuration of the gun was magazine fed, primarily using a 60 round drum magazine (an alternate 30 round box magazine was also available). The 20mm round is believed to be the Oerlikon designed 1SS. Practical sustained rate of fire was between 250 and 320 rpm. This gun used a 400-grain (26-gram) charge of  smokeless powder to propel a 2,000-grain (130-gram) projectile at 2,800 feet (850 meters) per second. Maximum range being 4,800 yds.

Given their rate of fire, combined with that of the .303 cal. Vickers 'K' guns on each of the squadron's 39 jeeps, it would be curious to know what the ammunition allowance was for the 1st Airborne Reconnaissance Squadron going into the operation. 

As can be seen from the photographs and drawings, manning the gun without the protection of any kind of shield could be hazardous. In the combat environment that existed at Arnhem and in the Oosterbeek perimeter it proved deadly.

Their employment in the battle is established in the following war diary entry;
"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."

In addition, a Dr. Clous, a dentist living in Oosterbeek at the time of the battle, was able to take limited movies during the early stages of the battle. In this particular single frame taken from that film, the reader can see one of the two 20mm Polsten guns comprising the section in the 1st Airborne Reconnaissance Squadron, in tow behind a jeep of the squadron. Given Dr. Clous' records we even know the location and date; Lebretweg 1, Oosterbeek, 18 September 1944. Because it is movie film, and old, the resolution leaves something to be desired.

It's not often that an author has the opportunity to cite information directly from original source documentation. The following is a copy of the actual page of the War Diary of the 1st Airborne Reconnaissance Squadron, Royal Armoured Corps, which specifically cited the above entries:

In the movie "A Bridge Too Far" there is a poignant scene where a British paratrooper loses his life trying to recover one of the few parachuted CLE resupply containers which landed within the shrinking perimeter of the airborne forces at Oosterbeek. When the container is finally opened, it contains nothing but a supply of new red berets. A lot of viewers would immediately interpret this as mere Hollywood injection of theatrical dramatics. In real life who would be so stupid. Read it for yourself on another page of the Squadron's War Diary:

If the viewer can't quite make out the entry, it says "... One contains berets the other an assortment of crowns, pips chevrons, & cap badges ...". Manna from heaven, perhaps for an insignia collector, absolutely not for beleaguered paratroops.

I was not aware at the initiation of this page, and it is with both acknowledgment and apologies, that I can relate to you that Philip Reinders (already 'mentioned in dispatches' elsewhere in this blog) has previously written a booklet on the very same subject. I'm not certain whether he has any copies left, but if anyone is interested he can be contacted at his new blog page; http://4thparachutebrigadearnhem1944.eu. Subsequently Philip has graciously contributed the following additions from his personal research and collection. The first being a photograph of Lieut Christie's grave stone, and the second an empty 20mm cartridge casing recovered from the battlefield.

In addition Colin MacGregor Stevens CD, retired Manager of the New Westminster Museum and Archives in British Columbia, Canada (also Captain (Rtd), Canadian Army), is an advanced airborne collector, and maintains a web page where he discusses in detail the 20mm Polsten as well as other 20mm weapon systems. In this discussion he details a special gun carriage called the “Mounting, Airborne, 20-mm Gun No.2 Mark 2 Land Service.” Colin further states;  “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.” With acknowledgment the following is a complete 20mm round from his collection. For those familiar with the design and configuration of machine cannon cartridges, note that the diameter of the base of the cartridge is smaller than the cartridge wall.

As a brief aside I had the opportunity to meet Colin decades ago (1977) while vacationing in Vancouver, British Columbia, and subsequently trading him original shoulder titles of the Commando SBS and Commando 'D' (Depot) for original formation badges of the 153rd and 154th Gurkha Parachute Battalions. Both of us were very pleased then, and certainly even more so today.

The following photographs are of a very rare fully restored 20mm Polsten taken at one of the recent Anniversary Commemorations of the battle, and the second of another gun integrated into a diorama at the Airborne Museum, Hartenstein Hotel.