In 1879, however, it was generally found that in average hands the .577/450 Martini–Henry Mk2, although the most accurate of the Martinis in that calibre ever produced for service life, was really only capable of hitting a man-size target out to 400 yards. This was due to the bullet going subsonic after 300 yards and gradually losing speed thereafter, which in turn affected consistency and accuracy of the bullet in flight. The 415-grain Martini Carbine load introduced in 1878 shot better out to longer ranges and had less recoil when it was fired in the rifles, with its reduced charge of only 75 grains of Curtis & Harvey's. It was found that, while the rifle with its 485 grain bullet shot point of aim to 100 yards, the carbine load when fired in the rifles shot high at the same range, but then made up for this by shooting spot-on out to . These early lessons enabled tactics to be evolved to work around the limitations of this large, slow, and heavy calibre during the Zulu War. During most of the key battles, such as Rorke's Drift and the Battle of Ulundi, the order to volley fire was not given until the Zulus were at or within 400 yards.