Trench warfare
Trench warfare prevailed on the Western Front from late 1914 until the Germans launched their Spring Offensive on 21 March 1918. After the buildup of forces in 1915, the Western Front became a stalemated struggle between equals, to be decided by attrition. Frontal assaults, and their associated casualties, became inevitable because the continuous trench lines had no open flanks. Casualties of the defenders matched those of the attackers, as vast reserves were expended in costly counter-attacks or exposed to the attacker's massed artillery. There were periods in which rigid trench warfare broke down, such as during the Battle of the Somme, but the lines never moved very far. The war would be won by the side that was able to commit the last reserves to the Western Front.
Mauser 1918 T-Gewehr
During the First World War the onset of static, trench warfare saw the rise in the use of armour plate for personal defense, and the development and use of armour-piercing ammunition to counter this. Both Britain and Germany used high-powered rifles, such as elephant guns from their African colonies, for this purpose.
The first use of armoured fighting vehicles (tanks) was by the British at the Battle of Flers–Courcelette in September 1916 and were followed by the French.
By June 1917, the German Army faced the Mark IV tank, and found that the standard armour-piercing 7.92 mm K bullet was no longer effective.
This prompted the development by the Germans of a heavy-calibre and high-velocity rifle as an anti-tank weapon.
The Mauser Company responded with the 13mm "T-gewehr" and began mass production at Oberndorf am Neckar in May 1918. The first of these off the production lines were issued to specially raised anti-tank detachments.