of and a length of . The main body of the shell was composed of thick steel, containing of TNT. The small amount of explosive – around 6.6% of the weight of the shell – meant that the effect of its shellburst was small for the shell's size. The thickness of the shell casing, to withstand the forces of firing, meant that shells would explode into a comparatively small number of large fragments, limiting their destructive effect. A crater produced by a shell falling in the Tuileries Garden was described by an eyewitness as being across and deep. The shells were propelled at such a high velocity that each successive shot wore away a considerable amount of steel from the rifled bore. Each shell was sequentially numbered according to its increasing diameter, and had to be fired in numeric order, lest the projectile lodge in the bore and the gun explode. Also, when the shell was rammed into the gun, the chamber was precisely measured to determine the difference in its length: a few inches off would cause a great variance in the velocity, and with it, the range. Then, with the variance determined, the additional quantity of propellant was calculated, and its measure taken from a special car and added to the regular charge. After 65 rounds had been fired, each of progressively larger caliber to allow for wear, the barrel was sent back to Krupp and rebored to a caliber of with a new set of shells. The shell's explosive was contained in two compartments, separated by a wall. This strengthened the shell and supported the explosive charge under the acceleration of firing. One of the shell's two fuzes was mounted in the wall, with the other in the base of the shell. The fuzes proved very reliable as every single one of the 303 shells that landed in and around Paris successfully detonated. The shell's nose was fitted with a streamlined, lightweight, ballistic cap and the side had grooves that engaged with the rifling of the gun barrel, spinning the shell as it was fired so its flight was stable. Two copper driving bands provided a gas-tight seal against the gun barrel during firing. Use in World War I The Paris gun was used to shell Paris at a range of . The gun was fired from a wooded hill (Le mont de Joie) near Crépy, and