By 1917, indirect fire with guns (as well as mortars and even machine guns) was commonplace, using new techniques for spotting and ranging, notably aircraft and the often overlooked field telephone.
Tahun 1917, tembakan tidak langsung dengan senjata (disertai mortir dan bahkan senjata mesin) biasa dilakukan, memakai teknik baru mencari dan mengukur, terutama pesawat dan telepon lapangan yang sering diabaikan.