Obice 305/17: Italy’s Huge Howitzer from WWI

One of the strangest looking artillery pieces from the First World War is the Obice 305/17 D.S., a massive 305 mm howitzer that served from 1914 all the way until 1959.

This howitzer was mounted on top of a weird mount that looks like a wooden horse. However it was actually a very clever design that simplified its use.



The Obice 305/17 starts in 1908, when the Italian Army realised that their then-current crop of 280 howitzers were no longer suitable for coastal defense. It was decided that weapons with a caliber of 305 mm (12 inch) at a minimum were needed.

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A heavy artillery piece that could provide effective long-range fires is particularly important for coastal guns, as they can deny the area within their range to enemy ships.

Obice da 280 howitzer.
The Obice da 280, a 280 mm coastal defense howitzer from the 1800s.

Major armament manufacturers of the day, like Krupp, Schneider, St. Chamond, and Armstrong were handed the requirements for this new howitzer and invited to propose their own designs.

Armstrong’s design was deemed best, and with a few changes, an example was ready by 1913. The howitzer, named the 305/17, entered production the following year and soon began being installed on coastal positions.

That same year though, the First World War began.

Obice 305/17 set up for firing.
An Obice 305/17, set up in its firing position.

This war very quickly highlighted the importance and limitations of artillery systems. Existing types often lacked the range and destructive power needed to breach the extensive trench networks and fortified positions that characterized the Western Front and other battlefields, and ones that could were in limited supply.

When Italy became involved in the First World War in 1915, it too sought to enhance its artillery capabilities to meet these challenges.

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They began removing the 305/17s from coastal positions, and paired them with towable mounts. By the end of 1915, twelve batteries of these howitzers had been established.

Obice 305/17 barrel on a carriage.
An Obice 305/17 barrel on its carriage, being used as a sea by soldiers in the First World War.

Design of the Obice 305/17

The Obice 305/17 was a very large weapon. Its barrel was 5.8 meters long and weighed 14 tons including the breech, which was a screw type.

On its basic box carriage mount, the 305/17 could elevate between +20° to +65°. The carriage alone weighed 16 tons, for a total weight of well over 35 tons for a complete gun and carriage.

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Over the course of the howitzer’s long service life it could fire a wide range of ammunition, with heavy and light shells ranging from 295 kg to 442 kg. With up to 16 charges of propellent, the 305/17′ furthest range was 9 miles (14 .6 km).

305/17 loading process.
Crews load a 305 mm projectile into the breech of a 305/17.

Maximum rate of fire was one round every 5 minutes, although the typical rate of fire was about one round ever 12 minutes.

Three hydraulic cylinders mounted on top of the gun cradle helped with recoil management. The maximum recoil travel with 960 mm.

A number of mounts were created for the howitzer throughout its service. Initially, its coastal mount was modified so it could be broken down into a number of smaller parts to facilitate transportation. This was designated the Modello 1916.

Obice 305 mm muzzle.
A 305/17, likely on a Modello 1916 mount, indicated by the rope around the barrel.

A position had to be cleared and prepared for the weapon, including digging a hole for a large, upside-down pyramid-shaped oak and iron ground anchor. Once on site, the 305/17 would be reassembled. This entire process took about 24 hours.

The 305/17 Modello 1916 could be rotated 360 degrees, however this was achieved by physically pulling on the barrel and carriage with ropes and hoists.

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The Modello 1917 refined the design, and added a hand crank system for traversing the howitzer. This version was divided into four parts for transport: the barrel, the cradle, the platform, and the ground anchor.

Obice howitzer parts loaded onto a train.
Train carriages loaded with the main components of a 305/17 howitzer. Starting from the left is the carriage, ground anchor and the barrel under a sheet. The platform is not visible.

305/17 De Stefano

The most famous version of the howitzer is the 305/17 D.S.. This version is extremely bizarre and resembles a giant, wooden horse. The “D.S.” in its name refers to its designer, artillery officer Antonio De Stefano.

De Stefano created a monstrous platform for the howitzer, which greatly simplified the process of transportation and set up for firing – at the cost of sheer size.

305/17 De Stefano mount.
The wild-looking De Stefano carriage. It was both the howitzer’s mount and mode of transportation.

The D.S. carriage was essentially a long box that contained the gun and its cradle inside at one end. The front wheels were rigidly attached to the carriage, while the rear wheels were on a pivoting mount so it could be maneuvered.

During transport, the wheels were fitted with large pads that helped to spread the carriage’s weight over a greater surface area and reduce its ground pressure.

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At its firing location, a wooden ground anchor was laid, on top of which was two metal rails. The De Stefano carriage would then be placed on top of the rails – after the pads had been removed from the wheels.

De Stefano mount being pulled on to the rails.
A De Stefano-mount 305/17 howitzer being pulled up onto the rails by two trucks.

The rails were slightly angled downward, and upon firing, the carriage would roll back along them, distributing the recoil as it went. The carriage then rolled forward back into battery, being slowed by hydraulic brakes on the front wheels.

For traverse, the rails were rotated with the carriage on top of them.

This system was much simpler than previous types, and was transported in only two loads. The De Stefano carriage could be towed into place and required minimal setup. It was, however, very heavy and large, which limited its practicality.

De Stefano mount captured.
A 305/17 D.S. that was abandoned by Italian forces and captured by German troops.

Service History of the Obice 305/17 D.S. Howitzer

The Obice 305/17 saw extensive service during the First World War, where it was used by Italian forces on various fronts, most notably against Austro-Hungarian fortifications along the Isonzo front.

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The howitzer’s ability to deliver powerful shells over long distances made it a valuable asset in Italy’s artillery arsenal, contributing to the breaking of entrenched enemy positions and supporting infantry assaults with preparatory bombardments.

305 mm projectile being moved on rails.
Crews move a 305/17 shell to the gun via rails.

The Obice 305/17 gained the title of the most powerful artillery piece used by Italy during the war.

They were regularly used in batteries of two howitzers, with a number of batteries usually assembled in one area. During the Second Battle of the Piave, for example, 29 guns had been gathered together.

Here, they were used to shell the rear staging areas of the Austro-Hungarian forces, essentially stifling the attack before it had even begun.

305/17 howitzer carriage in the Val Raccolana valley.
A large group of men pull a 305/17 howitzer carriage into position in the Val Raccolana valley.

The range and firepower of these weapons meant they were in very high demand wherever they were employed. Some were lost in battle, but they were of such high important that new examples were built to replace them.

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Following World War I, the Obice 305/17 D.S. continued to serve in the Italian Army, however the quantity had reduced significantly, likely due to barrels being worn out from usage. No De Stefano howitzers were in service a few years after the war, probably due to barrel wear and their impractical heft.

But the thing with large caliber weapons is that they have very long life spans. If it can throw a large projectile a reasonable distance, and there are stocks of ammunition available, it can still cause plenty of damage.

A 305/17 barrel on the Austrian-Italian border.
A 305/17 barrel on the Austrian-Italian border. This destroyed barrel may be the victim of over-usage.

Thus, by the time the Second World War rolled around, the 305/17 was still in Italian service.

The weapons saw some action, but due to their large size and weight it proved difficult for them to keep up with the much faster movements of this war.

By the end of the war, a few of the 305/17s had been positioned as coastal defense weapons, bringing their service life full circle back to their original role.

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Incredibly, the last 305/17s were removed from Italian service in 1959.