Krupp 120mm field howitzer M. 1892

The Krupp 120mm L/11.6 field howitzer had the same manufacture system and the same breech mechanism of the 87mm field guns, therefore it could be easily served by the gunners assigned to the artillery regiments. The barrel was built throughout of crucible steel and was composed by the tube without jacket. It was 11.6 calibres long, increasing twist, rifled with 36 grooves. It had the Krupp single motion wedge breech mechanism, with steel plate and gas check-ring; the crank could be removed to fire at high angles. It was fitted with arch sight with the centre pointed at the fore sight to obtain the fixed line of sight. It had three different graduations, adapted to the three different battering charge of the howitzer. The cover of the sight was provided with a spirit level and could be turned to correct the inclination of the trunnions.

The carriage was very similar to the carriage of the field gun, but the height of the trunnions was lower to reduce the vertical recoil, and this meant that often a rough ground or some shrubs could hinder the correct aim at the target. The wheels had the same height, but they and the axletree were reinforced. The gun wheels were different than the limber ones, so the spare wheels could not be use for both of them. The right trail side carried an elevating hand-wheel, that activated a shaft with a worm, two bronze toothed wheels, a pinion, and a toothed arc connected to the carriage by means of two bolts. The toothed wheels were unprotected, so they easily became dusty and dirty, and quickly corroded, making the elevation not proportional to the rotation.

The carriage was directly connected with the axle, without spring gears, and the stroke of the recoil was transmitted entirely to the carriage. In order to reduce the effect of the recoil, the howitzer was equipped with two different kinds of brakes. The wooden ones worked on the tires, while the iron ones had arched grooves that meshed with the grooves on the hub. They could reduce the recoil from 8 to 2-3 paces, but were regarded as complex and delicate : the wooden brakes wore quickly, and the grooves of the iron brakes became rusted and filled up with dust easily.

The carriage weighted 650 kg with the wheels and carried also 30 kg of tools and fittings, so that with the tube weighting 450 kg, the whole howitzer weighted 1130 kg.

The howitzer was equipped with two different loads, weighting 0.6 kg and 0.9 kg. They allowed preparing three blasting charges, depending on whether the howitzer employed the low load, the heavy load, or both together. At first the charges were composed by black powder with grains of 6mm – 10mm (Grobkörniges Artillerie-Pulver), later the howitzers were modified to employ the Rottweil smokeless powder, the charge weighting respectively 185 g, 285 g and 470 g.

The howitzer could fire three different kind of projectiles, all weighting 20 kg : a shrapnel, a cast iron and a steel shell. The only effective projectile, however, was the shrapnel, since the two kinds of shells did not contain enough powder to demolish strong buildings and fortifications. The shrapnel was equipped with a time and percussion fuze, which was graduated up to 30” for time fire against animate targets behind covers.

Later, in 1903, the Artillery Committee examined the question of the adoption of a torpedo shell, filled with a blasting charge powerful enough to destroy armoured and concrete shelters. The order was directed to the French firm Schneider-Canet that offered a shell filled with its own kind of high explosive, the Schneiderite. During the summer and the autumn a lot of comparative and laboratory tests were made and the results were presented to the Artillery Committee that on 10 March 1904 concluded that the Schneiderite was acceptable. Therefore the French firm received a great order of torpedo shells for both the 120 mm Krupp field howitzers and the 150 mm Schneider siege howitzers.

The howitzer was provided with some support wagons : a spare carriage, a field forge, and two different kind of store wagons. In order to cut the cost of the battery, the Bulgarian Army decided to assign only one store wagon, reducing the number of the items carried.