This heavy BL 6-inches 30 cwt Howitzer ('BL' = 'Breech Loading') was one the rare equipments of this kind available in August 1914. The 'Siege Brigade' bring 24 such guns in France, and another 100 were brought afterwards.

It was an obsolete type of howitzer, with a purely mechanical recoil system (springs). It could fire on wheels, or on a siege carriage that allowed higher elevation angles for a stronger destruction power en entranchments. In 1915, this howitzer was progressively removed from the active units and replaced by its successor, the BL 6 inches 26 cwt howitzer.

Main characteristics :

• Weight in firing position : 3508 kg
• Calibre : 152.4 mm (6 in.)
• Tube length : 15.6 calibres
• Projectile weight : 53.5 kg (old shell) - 45.3 kg (nouvel obus)
• Initial velocity : 237 m/s (old shell) - 326 m/s (nouvel obus)
• Maximum range : 4750 m (old shell) - 7400 m (nouvel obus)
• Elevation range : -10 / +35 degrees (on wheels) - -10 / + 70 degrees (on siege carriage)
• Direction range : 10 degrees