Shield vs steel bullets



On 15 August 1902 in Kaiser Wilhelm’s presence Krupp carried out some experiments to check the resistence of 3 mm hard steel plates against shrapnel filled with steel bullets, weighting 10 g. A 75mm L/30 Krupp field gun with a muzzle velocity of 500 m/s fired at 3500 m against a field battery in French formation, i.e. with the wagon body up-ended alongside the gun.

The gun fired 20 rounds. The range of shots was from 30 m to 130 m, 65 m on an average. The gun shield was hit by 80 bullets: 63 splinters (79%) pierced it right through. Among the 16 men (8 standing and 8 sitting) depicted behind the shells, 13 were hit by around 62 bullets (81 %).

The ammunition wagon shield, which was reinforced by the wooden wall of the wagon itself, was hit by 76 bullets: only 13 splinters (17%) pierced it right through. Among the 12 kneeling men depicted behind the shells, 9 were hit by around 14 bullets (75 %).

Another test was carried out against the carriage N° 4, this time without crew behind. The gun fired 11 more rounds to it. The range of shots was from 20 m to 110 m, 60 m on an average. The gun shield was hit by 55 bullets: 30 splinters (55%) pierced it right through.

Finally another shield was fired at 2000 m with shrapnel filled with hard lead bullets. This time no splinter pierced the shield.

On the other hand Rheinmethall later found that a 4 mm shield kept out the steel bullets even at short ranges. Therefore the German Army kept a 4 mm shield for its field guns, even if France had adopted a 5 mm shield, followed by most of the European armies that choose a thickness of 4 mm. Also for their horse artillery, where the reduction of the weight of the gun was essential, both France and Russia preferred a stronger 3.5mm shield.


As a consequence of these experiments, Krupp came to the conclusion that the adoption of steel bullets  would be favourable when one’s opponent were known to be equipped with gun shield of less than 4 mm thickness. However the use of steel bullets entailed a loss of efficiency against infantry, since the steel bullets, being less dense than the ordinary mixed metal bullets in the proportion of 8 to 9, did not carry so far and were less effective against troops in the open.

Moreover the larger size of the steel bullets sensibly reduced the number that could be packed in a shell. Actually Krupp found that its field shrapnel, which normally held 300 mixed metal bullets of 11 g, would only hold 265 steel bullets of 10 g.




3mm Krupp steel plates