This suggestion is based on an article in the Swedish armor magazine “Pansar” written by the creator of the vehicle modification himself and published by SPHF (Svensk PansarHistorisk Förening).
An artist’s rendition (seen above) was accompanied in the article which should be accurate, which I’ve further confirmed with the author. It shows a Volvo-variant of the KP-car (VKP) which is what the stats are based on.
History and Development
This is the story of a one-off vehicle made from mounting a Bofors 20mm “m/40B” autocannon on a “KP-Bil” armored car.
Sometime between 1953-1954, platoon leader Henry Wickström got the approval of General Frykman to transfer a “Bofors m/40 20mm autocannon” off of the Pansarbil m/31 (covered in another suggestion) and mount it on the KP-bil - mounting, coax MG, shield and everything with it. The gun was placed rearward, just behind the passenger’s wooden benches, and was bolted/screwed onto the hull floor. Shooting and driving vibrations did not degrade the mounting of the gun and it was considered very satisfactory, without any damages or cracks noted.
However, during firing tests a certain materiel officer by the name of Captain Folke took notice. Captain Folke disapproved of the modification and remarked on the so-called “damage” that had been done to the “[Swedish] Royal Crown’s vehicle” and ordered it to be restored immediately, in spite of the attempts of Wickström to make him see the sense of it. A sad end to what could have become a successful standard mobile AA platform. As Wickström noted, “…to rearm KP-cars with the automatic cannon from Pansarbil m/31, you could quickly have 30 KP-cars equipped for fire support and anti-air, in a time where you almost completely lacked mobile anti-air”. He nicknamed the modified vehicle the “KP-Bil Special”.
He further remembers that this all took place in 1954, to be specific.
Since this was before the dual AA MG modification the roof simply had a hatch bolted on the roof and the autocannon setup was the only armament.
The gun with the mount weighed 300kg (might be the wheeled variant. A similar variant (Automatkanon m/1941 - Hallands Militärhistoriska Museum / DigitaltMuseum) with an m/41 Akan and mount weighs 237kg ), that’s without the shield and coax MG. The coax MG would’ve weighed, unloaded, about 26kg with water. The shield’s weight is unknown but an example can be found at Arsenalen Museum mounted in the Pansarbil m/31 for measuring dimensions and thickness.
Separate Pictures of Vehicle and Armament (Only 3 pics)
^Towed ground variant of the armament. The vehicle used the gun on an AA mount with a co-axial MG and protective gun shield.
Credit: Bofors 20 mm automatkanon - 20 mm akan m40/70 | crusaderstgeorge | Flickr
^The armament on the Pbil m/31, which this vehicle would’ve operated together with, that was used on the KP-Bil “Special”. Note the depression.
I couldn’t find any image of the m/40B in its mount with the coax MG and shield, but if you google “Pansarbil m/31” or visit “Arsenalen Pansarmuseum” you can see it for yourself (I don’t want to flood this suggestion with Pbil m/31 images in case people mistake them for each other).
Pic of the m/40B mounted on the Pvlvv fm/42 in its own type of mount and shield in the game, with a drum magazine.
Name: VKP - Volvo Karosseri-Pansar.
Engine: Volvo FET 6-cyl gasoline, developing 105hp @ 2,500rpm.
Transmission: D-8, 4 forward, 1 reverse. 4x4 wheel drive.
Speed: 35 km/h off-road, 70 km/h on paved road. (Changes in top speed weren’t tested.)
Weight: Estimated ~7,300 kg, the modified vehicle was never weighed. It used the gun and mount from the “Pansarbil m/31” that was screwed/bolted onto the floor of the Volvo KP-bil.
Armor: 8-20 mm.
Main Armament: 20 mm automatkanon m/40B (20mm akan m/40B). M/40 variant in an AA-mount with a gun shield and co-axial MG.
Cyclic Rate: 360 RPM.
Bullet Velocity and Weight: 815-845 m/s, 139-145 grams.
Capacity/Feed: 25-round drum.
Elevation/Depression: -5°/+85° (according to Arsenalen Pansarmuseum’s technician Fredrik Bodin)
Sights: Iron sights (x1.0).
Ammunition: Mainly AP-T and HEFI-T (14g filler). Both types are already in the game (Pvlvv m/42 & Pbil m/40).
Ammunition Carried: Unknown, but since it was to be used as an AA With other Pbil m/31 it makes sense to carry a similar amount of ammunition. It might’ve carried more ammo since the gun (when towed) was originally used for anti-armor protection. Dual uses (anti-armor/air) could require more ammo, but that’s just speculation.
Secondary Armament: Water-cooled 8mm Ksp m/36 (mounted coaxially).
Cyclic Rate: 720 RPM.
Muzzle Velocity: 725-930 m/s (ammo dependent).
Capacity/Feed: 250-round belt.
- Svensk PansarHistorisk Förening (SPHF), Pansar nr 1, 2015 “KP-bil med 20 mm akan” by Henry Wickström. pp. 16-17.
- E-mail correspondence with the SPHF article writer, Christer Baadstöe, who had contact with Wickström himself (the designer of the vehicle).
- Terrängbil m/42 KP - Wikipedia - Wiki article of the base vehicle with the mention of the 20mm modification.
- m/40 automatic cannon - Wikipedia - Wiki on the armament.
- Bofors 20 mm automatkanon m/40 – Wikipedia - wiki on the armament (in Swedish).
Below are the emails (in Swedish) that I’ve exchanged that contains some of the information on the vehicle. The email address has been redacted for privacy reasons. I can forward the original emails to the mods for confirmation and validation if needed.
Below: First mail from SPHF article author.
Below: second mail from the author.
Below: Source on the elevatiod/depression of the gun.
This is an official contact email on Arsenalen’s website, therefore I didn’t censor it.
Edit: Added wiki pages for the vehicle and armament.