Historic context :

The 280mm Armstrong coastal mortar - delivered to the Japanese and used during the Russo-Japanese conflict - had shown its limitations, so in 1908 the Italian General Staff issued a call for tenders involving Vickers-Terni, Armstrong, Saint Chamond and Schneider. The project designed by Armstrong Pozzuoli won out, but it wasn't until 1914 that these new coastal artillery pieces became available, under the name 'Obice da 305/17 G modello 1915'.

This was a modern piece, with steel tubing, interrupted screw breech and recoil recovery system based on two hydraulic brake cylinders and a pneumatic recuperator. It was mounted on a 'Garrone' mount (giving the initial 'G' of the gun's official name) enabling 360-degree horizontal aiming.

Unlike its adversary Austria-Hungary, the Italian Army at the beginning of the 20th century had no powerful, modern heavy field or siege artillery. The idea therefore arose to use this modern 305/17 rib piece in this role, at the price of a relative lightening and a small adaptation of the Garrone carriage to make it dismountable. This 'Obice da 305/17 G modello 1916', was later further modified into the 'Obice da 305/17 G modello 1917' to enable the disassembled parts to be pulled by automotive machines.

Finally, a 'Obice da 305/17 DS' version using the De Stefano carriage saw the light of day. This strange but ingenious dismountable ground mount had several original features:

• it had 2 fixed wheels at the front and two steerable wheels at the rear, enabling the gun to be transported with the chassis
• these wheels could be fitted with cingolis for movement over soft ground
.
• for firing, the chassis was mounted on inclined rails in which the wheels moved, ensuring an exact return to exact position after the part recoiled, incompletely absorbed by the brake-recovery system
• the rails were mounted on a wooden platform enabling firing with 360-degree horizontal aiming
• The height of the carriage ensured that the breech remained accessible for shell loading even at high firing angles
.

Technical data :

• Complete description : 305/17 Howitzer
• Design year : 1914
• Calibre : 305.00 mm
• Weight in firing position : 33.7 tons
• Weight for transportation :
• Tube length in calibres : 17.00 (19 calibres breech included)
• Grooves : 60 constant angle, left handed
• Projectile weight : 295–442 kg
• Initial speed : 545 m/s
• Fire rate : 1 round / 5 min to 12 min
• Range : 17600 m-
• Elevation range : -20 to +65 degrees
• Direction range : 360 degrees total range