Panzerserra Bunker- Military Scale Models in 1/35 scale: 21 cm Mörser 18 - German heavy howitzer

Artilleristen des Deutschen Reiches!!!

After a long, long break, I'm back to work in our Bunker!!! Today, we're going to talk about the 21 cm Mörser 18, one of the most technically sophisticated heavy artillery pieces used by the Wehrmacht during World War II. Designed to replace the World War I howitzer (the 21 cm Mörser 16), the Mörser 18 introduced engineering innovations that set a new standard for German siege and corps artillery pieces. Lass uns gehen!!

German gunners prepare to fire a 21cm Morser 18 heavy howitzer
on French fortification positions. France, May-1940.

History:

The 21 cm Mörser 18 (21 cm Mrs 18), or 21 cm Mörser M 18/L31, was a German heavy howitzer used in the Second World War by Independent artillery battalions and batteries. A number were also used by coastal artillery units.

Soldiers positioning a 21 cm Mörser 18 from a coastal battery.
Somewhere in Norway, Lapland or Finland (1943).

A 21 cm Mörser 18 in Norway, as coastal battery, gun.

Design

The Mörser 18 was designed to replace the obsolescent World War I-era 21 cm Mörser 16. The gun design itself was not significantly different from its predecessor but the carriage was improved considerably.

A German 21 cm Mörser 16 being brought into position in the Ham area, France - 1918.

It was one of the first artillery pieces that incorporated a dual-recoil system. The barrel retracted naturally in its cradle, and the entire top carriage - which held the barrel and its cradle - retracted across the body of the carriage as well. This system damped out the recoil forces and made for a very steady firing platform. This carriage was also used for the 17 cm Kanone 18 in Mörserlafette and the 15 cm Schnelladekanone C/28 in Mörserlafette.

A 17 cm Kanone 18 in Mörserlafette firing in Tunisia, 1943.

A 17 cm Kanone 18 emplaced outside the Anzio beachhead. Italy, 1944.

A 15 cm Schnelladekanone C/28 in Mörserlafette in the Russian front

The 21 cm Mörser 18 was transported in two pieces, as was often the case for similarly sized weapons. For travel the barrel was slid on to a separate trailer. The carriage carried an integral firing platform that was lowered to the ground when emplacing the howitzer. The wheels were then cranked up off the ground and it was now ready for firing. A rear castor-wheel jack was used to raise the rear spade off the ground if the gun needed to be traversed more than the 16° allowed by the mount proper.

The heavy howitzer entered production at a low rate in 1939 shortly before the war began. The Germans cancelled production in 1942 in lieu of its smaller brother, the 17 cm Kanone 18 in Mörserlafette, which could fire almost twice as far, but resumed production in 1943.

21 cm Mörser 18 heavy howitzers somewhere in Russia during Barbarossa.

Beginning in 1942, the 21 cm M 18 was one of a pair of weapons to have been mounted on production Geschützwagen Tiger self-propelled guns. A prototype was under test at the end of the war and was captured by American forces.

The abandoned prototype chassis of the Geschützwagen Tiger für 17cm K72 (Sf)
IWM (STT 9103)

A 21 cm Mörser 18 abandoned by the roadside on the road to Amiens, France, 1944.

Specs:

21 cm Mörser 18
Type	Heavy howitzer
Place of origin	Germany
Service history
In service	1939–45
Used by	Nazi Germany
Wars	World War II
Production history
Designer	Krupp
Designed	1933
Manufacturer	Krupp
Produced	1939–45
No. built	711+
Specifications
Mass	16,700 kg
Barrel length	6.51 m - L/30

Shell	separate-loading cased ammo (6 charges)
Shell weight	113 kg (HE)
Caliber	211 mm
Breech	horizontal sliding-block
Recoil	dual-recoil hydro-pneumatic
Carriage	box trail
Elevation	-6° to +70°
Traverse	16° on wheels 360° on platform
Muzzle velocity	550–565 m/s
Effective firing range	16.725 m

The kit:

This big artillery piece was one of my last projects of 2025. I built it as soon as I had the opportunity to get my hands on one of this model. I had become curious about the 21cm after building its younger and more powerful brother, the 17cm Kanone, already described here. The Trumpeter German 21cm Mörser 18 kit (#02314) is from 2010, well-injected and equipped, with metal parts and vinyl tires for the wheels, as already described in the 17cm Kanone. In fact, the parts of the 21cm and 17cm are the same, except for the gun barrels and some details on the gun cradles.

Trumpeter German 21cm Mörser 18 kit (#02314) with Kojak, in my workbench.

The contents of the box.

Starting by the booklet

Alignment is very important.

Right side of the chassis and carriage frame

Left side of the chassis and carriage frame

Adding details...

Many circular injection marks...

Chassis in firing position. Left view.

Right view

Details of the rear chassis coupling. Right view.

Details of the rear chassis coupling. Left view.

Unlike what I did with the 17cm Kanone, I reused the original springs,
as the metal diameter was acceptable.

The springs in position. Right view.

The springs in position. Left view.

Installing the wheels onto the chassis,
with perfect alignment.

Dry-run

Attaching the front fender brackets.

Front fenders with PE

Attaching the front fenders to the chassis support. Left view.

Attaching the front fenders to the chassis support. Right view.

Building the weapon's cradle.

Rear view.

Building the heavy howitzer cannon.

The breech is in position.

The large 21 cm cannon under construction.

Hydraulic shock absorbers of the howitzer's elevation system in position.
Left view.

Right view.

Chassis steering bogie suspension limiters

With the construction finished, I decided to settle my girl in Kursk.

Panzerserra guide of markings and colors.

Based on this fantastic book, I made the tactical marking decals for the 21 cm.

Painting the kit in dark yellow and its tonal variations.
Left view.

Painting the kit in dark yellow and its tonal variations.
Right view.

Installing the wheels and tires.

Other decals I made: battery markings and a table of distances
and elevation on the weapon.

Some details in color

Rear view.

With the weathering characterizations completed, my project is finished: here it is, 21 cm Mörser 18 - German heavy howitzer, serving in the 4. Panzer-Armee, serving in the schwere Artillerie-Abteilung 767, in the 3. Batterie, with the designation "Caesar", a typical name starting with C, designating the 3rd battery.