Test of the 53mm Fahrpanzer in Sofia

On 24 and 26 June 1891 the firm Grusonwerk of Magdeburg made severe test in the proving ground of Sofia in order to show the performances of the of 53mm Fahrpanzer recently designed by major Maximilian Schumann. A similar test had been made in Belgrade in May, and was repeated at Hademköi, near Istambul, in December, this time with a 57mm gun. The work schedule was prepared by the Bulgarian War Minister, col. Mihail Savov, and was aimed to appreciate the effect of a quick-firing light calibre gun against both animate and inanimate targets.

The gun was charged with 130 g of Kubische pulver M. 89, with a grane of 1.5mm, that had been tested in 1890, proving to be more performant and more powerful of the black powder used previously. The result were regarded as satisfactory, but the Bulgarian Army decided to adopt the more powerful 57mm gun, that had proved to be as much satisfactory in the tests performed at Tangerhütte in 1891, and at Hademköi in 1892.

Test effected on 22 June (4 July) 1892.

Fire at a range of 2000 m. The gun was placed on a temporary emplacement and was served by a worker of the firm Gruson, and a Bulgarian cannoner. The target was three rows of panels representing foot soldiers, 20 m wide, 1.80 m high, placed at intervals of 15 m. The gun fired 12 ring shells within the space of 28 seconds.

The ranging fire was hampered and slowed down by the low density of air, due to the altitude of the proving ground and the high temperature (36°). It was carried out firing two shot at every elevation and was judged very effective, since it assured an exact observation of the fires without an appreciable delay in ranging, thanks to the easiness of handling the gun, which enabled to fire two shots within a brief interval.

The results of the fire were as follows :

1^st row : 12 lines hit by 25 splinters and 3 shells or shell-heads;

2^nd row : 39 lines hit by 312 splinters and 6 shells or shell-heads;

3^rd row : 33 lines hit by 201 splinters and 8 shells or shell-heads;

Therefore 84 lines out of 120 were hit (70%) by 538 splinters or shells. The file of the central row were so thoroughly minced that was quite impossible to count the hits.

Fire at a range of 1200 m. The target was arranged in the same way. The gun fired 12 ring shells and 10 shrapnel. The shell were fired first within the space of 24 seconds; then 2 shrapnel were fired in order to verify the time of flight, finally the remaining 8 shrapnel with fuzes set in advanced were fired in only 16 seconds. The average height of burst was 2,5 m.

All together 119 lines out of 120 were hit by 187 bullets, 448 splinters, and 40 shells, shell-heads or fuzes.

Fire with case shot. The gun fired at first 5 shots at ordinary fire, then two series of 20 shots each at rapid fire, within an average space of 47 seconds. All the lines were hit by 1682 balls overall. Since the balls were 2690 in all (45 rounds with 82 balls each), their output was 46%.

Test effected on 24 June (6 July) 1892.

Fire against shooters. The target was a line of laying down shooters placed at intervals of 2 m, and represented by dummies at an unknown distance. Behind them there was a support force sheltered by an embankment, and represented by 20 dummies at unknown intervals. To appreciate the effect of a short-lasting fire, the gun, after the adjustment, should fire 22 ring shells and 10 shrapnel in 3-4 minutes time.

The range (1800 m) was obtained with an adjusting fire of 4 shells, then the gun fired 6 shots against middle of the line of the shooters, and 3 shots against each wing. Afterwards 3 shrapnel were fired in order to verify the time of flight, while the remaining 6 shrapnel with fuzes set in advanced were fired in only 12 seconds. Finally the remaining 6 shells were fired within the space of 15 seconds.

The results were judged very satisfactory, since 46% of dummies of the first line, and 30% of the support line were hit, although only few ammunitions were assigned, and the target was not clearly visible, being hidden by bushes.

Fire against a field battery. The target was a two guns field battery with 7 gunners each placed in open ground, with the limber unhooked behind, both at an unknown distance. Guns, limbers and gunners were represented by dummies. To appreciate the effect of light calibres against field artillery, the gun, after the adjustment, should fire 23 ring shells.

The range (1800 m) was obtained with an adjusting fire of 6 shells, then the gun fired 9 shots at rapid fire against the right gun in 18 seconds, and 8 shots against the left gun in 17 seconds.

The results were as follows :

- right piece : gun – 1 splinter and 12 holes, 2 gunners - 2 splinters and 12 holes, limber – 2 splinters;

- left piece : gun – 1 splinter, 3 gunners - 2 splinters and 8 holes, limber – 4 splinters and 27 holes.

Observation of fire. In either way the observation of the burst of the shells and shrapnel at a distance of 1800 m was very satisfactory, considering the light calibre of the gun.

Gruson 53mm M. 1889