A lightened and thus more portable version of the MG08 was tested as a prototype in 1915 by a team of weapon designers under the direction of a Colonel Friedrich von Merkatz—the MG08/15. The MG08/15 had been designed to be manned by four trained infantrymen spread on the ground around the gun and in the prone position. To accomplish that purpose the MG08/15 featured a short bipod rather than a heavy sled mount tripod, plus a wooden gunstock and a pistol grip. At 18 kg, the MG08/15 was lighter and less cumbersome than the standard MG08 since the MG08/15 had been designed to provide increased mobility of infantry automatic fire. It nevertheless remained a bulky water-cooled weapon which was quite demanding on the quality and training of its crews. Accurate fire was difficult to achieve and usually in short bursts only. It was first introduced in battle during the French "Chemin des Dames" offensive in April 1917 where it contributed to the very high casualty count among the French assailants. Its deployment in increasingly large numbers with all front line infantry regiments continued in 1917 and during the German offensives of the spring and summer of 1918. The MG08/15 became, by far, the most common German machine gun deployed in World War I (Dolf Goldsmith, 1989) since it reached a full allocation of six guns per company or 72 guns per regiment in 1918. By that time, there were four times as many MG08/15 light machine guns than heavy MG08 machine guns in each infantry regiment. To attain this goal, about 130,000 MG08/15 had to be manufactured during World War I, most of them by the Spandau and Erfurt government arsenals.
An air-cooled and thus water-free and lighter version of the MG08/15, designated as the MG08/18, was battlefield tested in small numbers during the last months of the war. The MG08/18's barrel was heavier but it could not be quick-changed, thus overheating was inevitably a problem. It would take the much later MG34, yet to come, to achieve that indispensable flexibility.
The word 08/15 lives on as an idiom in colloquial German, 08/15 (pronounced Null-acht-fünfzehn, or more colloquially Null-acht-fuffzehn), being used even today as an adjective to denote something totally ordinary and lacking in originality or specialness.
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