Brummbär

The Brummbär, officially the Sturmpanzer IV, was a German assault howitzer of the Second World War, mounting a 150 mm gun in a heavily armoured casemate on a Panzer IV chassis. The name Brummbär, meaning “grumbling bear”, was a nickname given by Allied intelligence — the Germans called the vehicle the Sturmpanzer IV — but it has become the name by which the vehicle is best known. About 306 Brummbärs were built between 1943 and 1945, and the vehicle was designed for close infantry support in street fighting and against fortified positions, where its large high-explosive shell could demolish buildings and bunkers that smaller guns could not. The Brummbär served on the Eastern Front, in Italy and on the Western Front, and it was used in the battles for Stalingrad’s aftermath, at Kursk, in the Warsaw Uprising and in the Ardennes. Its heavy armour and powerful gun made it a formidable weapon in urban combat, but its low ammunition capacity, its slow rate of fire and its limited numbers meant that it was never a decisive weapon. The Brummbär remains one of the most distinctive German armoured vehicles of the war, a heavy assault gun built for a specific and brutal kind of fighting.

1. Key Facts

Type	Assault howitzer / Sturmpanzer
Origin	Germany
In service	1943–1945
Number built	About 306
Crew	5 (commander, gunner, loader, driver, radio operator)
Weight	About 28.2 tonnes
Armour	Up to 100 mm front, 30–50 mm sides
Main armament	15 cm StuH 43 (150 mm) howitzer
Engine	Maybach HL 120 TRM, 12-cylinder petrol, 300 hp
Top speed	About 40 km/h on roads
Operators	Germany

2. Development

The Need for a Heavy Assault Gun

The Brummbär grew out of the German Army’s experience at Stalingrad in 1942–1943, where the fighting in the ruined city showed the need for a heavily armoured vehicle with a large-calibre gun that could demolish buildings and bunkers at close range. The StuG III, with its 7.5 cm gun, was not powerful enough for this role, and the German Army wanted a vehicle that could fire a large high-explosive shell from a protected casemate. The Army Weapons Office ordered a new assault howitzer based on the Panzer IV chassis, mounting a 150 mm howitzer, and the design was assigned to the Alkett company, which had built the StuG III. The first prototype was ready in early 1943, and the vehicle entered production in April 1943.

Alkett and the Sturmpanzer IV

The Brummbär was built by Alkett in Berlin, using Panzer IV chassis supplied by Krupp and Nibelungenwerk. The vehicle’s superstructure was a new design: a boxy, heavily armoured casemate with 100 mm of frontal armour, mounting the 15 cm StuH 43 howitzer, a version of the 15 cm sIG 33 infantry gun adapted for vehicle mounting. The gun was mounted in a ball mantlet that allowed a limited traverse, and the casemate had a low silhouette, about 2.5 metres high. Production was slow, because the casemate was complex and the gun was in demand for other weapons, and only about 306 vehicles were built by the end of the war, in four production series with minor improvements.

Production Series

The Brummbär was built in four series. The first series, built in 1943, had a 100 mm frontal plate, a driver’s visor and a relatively simple superstructure. The second series, built in 1943–1944, had a redesigned superstructure with a commander’s cupola and a ball-mounted machine gun. The third series, built in 1944, had a lighter superstructure and a different gun mounting, and the fourth series, built in 1944–1945, had a further redesigned superstructure and a driver’s periscope. The differences between the series were minor, and the vehicle’s basic design did not change. Production ended in March 1945, when the Alkett factory was damaged by bombing and the German war economy collapsed.

3. Design

Casemate and Armour

The Brummbär’s casemate was its most important feature: a heavily armoured, boxy superstructure with 100 mm of frontal armour, 50 mm on the sides and 30 mm on the rear, which gave the vehicle good protection against anti-tank guns at normal ranges. The frontal armour was sloped in the later series, and the casemate was designed to deflect shells and to protect the crew from small-arms fire and shell splinters. The casemate’s roof armour was 20 mm, and the vehicle was vulnerable to air attack and to artillery, as were all casemate vehicles. The Brummbär’s low silhouette and thick frontal armour made it well suited to its role as an assault gun, where it had to advance into the fire of enemy infantry and anti-tank guns.

Chassis and Running Gear

The Brummbär used the Panzer IV chassis with its four large road wheels, leaf-spring suspension and rear drive sprocket, and the Maybach HL 120 TRM engine of 300 hp. The chassis was reliable and well understood, and spare parts were shared with the Panzer IV, which was an advantage. The vehicle’s weight, about 28.2 tonnes, was heavier than the Panzer IV’s, and its top speed was about 40 km/h on roads and about 20 km/h cross-country. The Brummbär’s mobility was adequate for its role, though it was not a fast vehicle, and its range was about 210 km on roads. The chassis was, however, overloaded by the heavy casemate and gun, and the suspension wore out quickly.

Crew and Interior Layout

The Brummbär had a crew of five: a driver at the front left, a radio operator beside him, and a commander, gunner and loader in the casemate. The loader’s job was hard work: the 150 mm shells weighed about 38 kg each, and the loader had to lift them from the ammunition racks and load them into the gun, which had a rate of fire of only about 3 to 4 rounds per minute. The interior was cramped, because the large gun and its ammunition took up most of the space, and the crew had limited room to move. Ammunition stowage was only about 38 rounds, which was low, and the vehicle often had to be resupplied by a companion vehicle carrying extra ammunition.

4. Technical Specifications

Dimensions and Weight

The Brummbär measured about 5.93 metres long, 2.88 metres wide and 2.52 metres high, with a ground clearance of about 0.4 metres. Combat weight was about 28.2 tonnes, which was heavy for a Panzer IV chassis, and the vehicle’s weight was a result of its thick armour and its large gun. The Brummbär could cross a trench about 2.3 metres wide, climb a vertical obstacle of about 0.6 metres, and ford water up to about 1 metre deep. Its dimensions were similar to the Panzer IV’s, though its height was greater because of the casemate.

Engine and Performance

The Maybach HL 120 TRM was a 12-cylinder, water-cooled petrol engine producing 300 hp at 3,000 rpm, driving through a five-speed gearbox. The power-to-weight ratio of about 10.6 hp per tonne gave the Brummbär adequate but unremarkable performance, and fuel consumption was high: the 470-litre fuel tank gave a road range of about 210 km and a cross-country range of about 130 km. The engine was the same as the Panzer IV’s, and maintenance units were familiar with it, but the vehicle’s weight put a strain on the engine and the transmission, and breakdowns were common.

Protection in Detail

Frontal armour was 100 mm on the casemate front and 80 mm on the hull front, both well sloped in the later series. Side armour was 50 mm on the casemate and 30 mm on the hull, with 5 mm Schürzen plates on many vehicles. Rear armour was 30 mm, and roof armour was 20 mm. The Brummbär’s frontal armour was thick enough to stop the Soviet 76.2 mm gun and the British 6-pounder at normal ranges, and it gave the vehicle good protection in its assault role. The side and rear armour were thinner, and the vehicle was vulnerable to flanking fire, but in its intended role — advancing directly towards enemy positions — its frontal protection was its main asset.

5. Armament

The 15 cm StuH 43 Howitzer

The Brummbär’s main armament was the 15 cm StuH 43, a 150 mm howitzer with a barrel length of 12 calibres, firing a 38 kg high-explosive shell at a muzzle velocity of about 240 m/s. The gun’s range was about 4,200 metres, but it was normally used at much shorter ranges, often under 1,000 metres, where its large shell could demolish buildings, bunkers and fortifications. The gun’s high-explosive shell was its main weapon, and it was devastating against infantry in buildings and against light fortifications. The gun could also fire a hollow-charge anti-tank round, though this was rarely used, because the Brummbär was not intended as a tank destroyer.

Firepower in Urban Combat

In urban combat, the Brummbär’s 150 mm shell was a formidable weapon. A single hit could collapse a building, destroy a barricade or kill the occupants of a room, and the gun’s large blast effect made it effective against infantry in cover. The Brummbär was used in the Warsaw Uprising in 1944, where it fired at Polish positions in the city, and in the battles for German cities in 1945, where it was used against Soviet and Allied infantry in buildings. The gun’s low muzzle velocity and its short range were not disadvantages in urban combat, where the targets were close and the gun’s large shell was more important than its range or accuracy.

Secondary Armament and Ammunition

The Brummbär’s secondary armament was a 7.92 mm MG 34 machine gun, mounted in a ball mount in the casemate front on the later series, and the crew carried personal weapons. Ammunition stowage was about 38 rounds for the 150 mm gun, which was low, and the vehicle’s rate of fire was only about 3 to 4 rounds per minute, because the shells were heavy and the loader had to work hard. The low ammunition capacity and the slow rate of fire were the Brummbär’s main weaknesses as a weapon, and the vehicle was often accompanied by an ammunition carrier. The Brummbär’s secondary armament was adequate for close defence, but the vehicle relied on its main gun and on accompanying infantry for protection.

6. Variants

The Four Production Series

The Brummbär was built in four production series, with minor differences in the superstructure, the gun mounting and the driver’s position. The first series had a simple superstructure with a driver’s visor and no machine gun mount. The second series had a commander’s cupola and a ball-mounted machine gun. The third series had a lighter superstructure and a different gun mounting, and the fourth series had a redesigned superstructure with a driver’s periscope and a simplified gun mounting. The differences were minor, and the vehicle’s performance did not change significantly between the series. Total production was about 306 vehicles, with the first series accounting for about 52 vehicles, the second for about 123, the third for about 80 and the fourth for about 51.

The Sturmpanzer IV Command Version

A small number of Brummbärs were built as command vehicles, with additional radio equipment and a reduced ammunition load. These vehicles were used by the commanders of the Sturmpanzer battalions, and they were distinguished by their extra antennae. The command version was built in very small numbers, and it was not a separate production series, but a modification of the standard vehicle. Command Brummbärs carried a second radio set and a frame antenna on the rear deck, and their crews included an extra signaller, which reduced the already small ammunition stowage still further.

Other Proposals

Several other variants of the Brummbär were proposed, including a version with a 15 cm StuH 43/1 gun and a version with a different chassis, but none entered production. The Brummbär’s chassis was also considered as a basis for other assault guns, but the German Army’s limited production capacity meant that the Brummbär remained a small-scale weapon. The vehicle’s production was, in the end, a minor part of Germany’s armoured vehicle programme, and its numbers were never enough to make it a standard weapon.

7. Combat Record

Kursk and the Eastern Front

The Brummbär first saw combat at Kursk in July 1943, where it equipped the 216th Sturmpanzer Battalion and was used in the attack on the Soviet defences. The vehicle’s 150 mm gun was effective against Soviet fortifications, but its numbers were small — only about 40 vehicles were available — and its impact was limited. On the Eastern Front the Brummbär served in the defensive battles of 1943–1944, and in the retreats of 1944–1945, where it was used to support infantry in the defence of cities and villages. The vehicle’s heavy armour and powerful gun made it useful in the defensive role, but its low numbers and its mechanical unreliability limited its effectiveness.

Italy and the Warsaw Uprising

In Italy the Brummbär served with the 216th Sturmpanzer Battalion in the battles around Anzio and Cassino, where its 150 mm gun was used against Allied positions in buildings and in the mountains. The vehicle’s service in Italy was limited by the terrain and by the Allied air superiority, and many vehicles were lost to air attack and to mechanical failure. In the Warsaw Uprising in August–October 1944, Brummbärs were used by the German forces to demolish Polish positions in the city, and their 150 mm shells were devastating against the barricades and buildings held by the Polish Home Army. The Brummbär’s service in Warsaw was one of its most notorious uses, and it showed the weapon’s effectiveness in urban combat.

The Western Front and the Ardennes

On the Western Front the Brummbär served in Normandy, in the Ardennes and in the defence of Germany in 1944–1945. In the Ardennes offensive of December 1944, Brummbärs were used to support the infantry in the attack on American positions, and their 150 mm guns were effective against the villages and towns held by the Americans. By the end of the war, most Brummbärs had been lost, and the survivors were few. The vehicle’s combat record was, in the end, a story of a powerful weapon built in too small numbers to make a decisive difference, but one that was feared by the infantry who faced it.

8. Operators

Germany

Germany was the Brummbär’s only operator. The vehicle equipped the Sturmpanzer battalions of the German Army, including the 216th, 217th, 218th and 219th Sturmpanzer Battalions, which were independent units attached to armies and army groups as needed. The Brummbär was never a standard weapon of the panzer divisions, and its service was limited to these specialist battalions. The vehicle’s numbers were small, and its service was, by necessity, concentrated where its heavy gun was most needed.

Captured Vehicles

The Western Allies and the Soviet Union captured Brummbärs in small numbers, and several were tested at proving grounds in Britain, the United States and the Soviet Union. The Allies were impressed by the vehicle’s armour and its gun, but they did not put it into service, because they had their own assault guns and because the Brummbär’s production was too small to be significant. Captured Brummbärs were used for trials and for display, and several survive in museums today.

Post-War Use

After the war, the Brummbär was not used by any army, and the type was retired. The vehicle’s design was not taken up by any post-war army, though the concept of a heavily armoured assault howitzer was continued in the Soviet SU-152 and ISU-152, which were larger and more powerful. The Brummbär’s post-war legacy was in museums and in the memory of the soldiers who faced it, and in the lessons it taught about urban combat.

9. Legacy

Urban Combat

The Brummbär’s main legacy is as a weapon designed for urban combat, and its service in Warsaw, in Italy and in Germany showed the importance of a heavily armoured vehicle with a large-calibre gun in street fighting. The lessons of the Brummbär influenced post-war thinking about urban warfare, and the Soviet Union’s continued use of heavy assault guns in the post-war period was in part a result of the German experience. The Brummbär’s design — a heavy casemate with a large howitzer on a tank chassis — was a logical solution to the problem of urban combat, and it remains a valid concept today.

Survivors and Memory

Several Brummbärs survive in museums, including the German Tank Museum at Munster, the Musée des Blindés at Saumur, the Kubinka Tank Museum in Russia and the United States Army Ordnance Museum. The vehicle is a popular subject for modellers, and its distinctive boxy casemate and its 150 mm gun make it instantly recognisable. The Brummbär is remembered as one of the most distinctive German armoured vehicles of the war, and as a weapon that was feared by the infantry who faced it in urban combat.

Assessment

Historians generally judge the Brummbär as a good weapon built in too small numbers. Its gun was powerful, its armour was thick and its design was sound, but its low ammunition capacity, its slow rate of fire and its limited production meant that it was never a decisive weapon. The Brummbär’s service in 1943–1945 showed that the German Army understood the need for a heavy assault gun, but that its industry could not produce enough of them to make a difference. The vehicle remains, however, an interesting example of a specialised weapon designed for a specific kind of fighting, and its story is a reminder that in war, numbers matter as much as quality.

10. FAQ

How many Brummbärs were built?

About 306 Brummbärs were built between April 1943 and March 1945, by the Alkett company in Berlin. The total includes four production series with minor differences, and production was limited by the complexity of the casemate. Production was also limited by the demand for Panzer IV chassis and 150 mm guns for other weapons, and the vehicle was never built in large numbers. The Brummbär was a German assault howitzer, mounting a 150 mm gun in a heavily armoured casemate on a Panzer IV chassis, designed for close infantry support.

What does Brummbär mean?

Brummbär means grumbling bear in German, and it was a nickname given by Allied intelligence, not an official German designation. The Germans called the vehicle the Sturmpanzer IV, meaning assault tank Mark IV, and it was officially the Sturmpanzer IV. The nickname Brummbär has become the name by which the vehicle is best known in English, and it remains one of the most distinctive German armoured vehicles of the war. The vehicle mounted a 150 mm gun in a heavily armoured casemate on a Panzer IV chassis, and it was designed for street fighting and against fortified positions.

What gun did the Brummbär carry?

The Brummbär carried the 15 cm StuH 43, a 150 mm howitzer firing a 38 kg high-explosive shell. The gun was a version of the 15 cm sIG 33 infantry gun, adapted for vehicle mounting, and its large shell could demolish buildings and bunkers. The gun was devastating in urban combat, and the Brummbär was designed for close infantry support in street fighting and against fortified positions. The vehicle’s heavy armour and powerful gun made it a formidable weapon in urban combat, but its low ammunition capacity and slow rate of fire limited it.

Was the Brummbär a tank destroyer?

No, the Brummbär was an assault howitzer, not a tank destroyer, and it was designed for close infantry support, to demolish buildings and fortifications, not to fight tanks. Its 150 mm gun could fire a hollow-charge anti-tank round, but this was rarely used, and the vehicle’s role was infantry support, not anti-tank warfare. The Brummbär served on the Eastern Front, in Italy and on the Western Front, in street fighting and against fortified positions. Its heavy armour, up to 100 mm at the front, and its powerful gun made it formidable in urban combat, but its limited numbers meant it was never a decisive weapon.

What was the Brummbär’s crew?

The Brummbär had a crew of five: a driver, a radio operator, a commander, a gunner and a loader. The loader’s job was hard work, because the 150 mm shells weighed about 38 kg each, and the rate of fire was only about 3 to 4 rounds per minute. Ammunition stowage was about 38 rounds, and the vehicle’s low ammunition capacity and slow rate of fire were among its weaknesses. The Brummbär weighed about 28.2 tonnes, with armour up to 100 mm at the front, and it carried the 15 cm StuH 43 howitzer.

Where can I see a Brummbär today?

Surviving Brummbärs are displayed at the German Tank Museum in Munster, the Musée des Blindés at Saumur in France, and the Kubinka Tank Museum in Russia. They are also displayed at the United States Army Ordnance Museum, among others, and the vehicle is a popular subject for modellers. Its boxy casemate makes it easy to identify, and about 306 Brummbärs were built between April 1943 and March 1945. The Brummbär was a German assault howitzer, mounting a 150 mm gun in a heavily armoured casemate on a Panzer IV chassis, designed for close infantry support.

11. Sources

• Chamberlain, Peter and Doyle, Hilary. Encyclopedia of German Tanks of World War Two. Arms and Armour Press, 1999.
• Jentz, Thomas. Panzertruppen, Volume 2: The Complete Guide to the Creation and Combat Employment of Germany’s Tank Force, 1943–1945. Schiffer, 1996.
• Spielberger, Walter. Sturmartillerie and Panzerjäger. Schiffer, 1993.
• Zaloga, Steven. German Assault Guns of World War II. Osprey.