Other positive features of the eighteen-pounder included a shield to defend against bullets, though not against other shells, so that the gunners were less exposed in their dangerous task.
It also had a sighting system: “The carriage is fitted on the left side with a rocking bar sight with sight clinometer, and No. 4 sighting telescope. It is provided with a No. 1 dial sight or No. 7 dial sight and No. 2 carrier.” (2) Got it?
Such a sighting system allowed for indirect fire – that is, aiming and firing at targets that weren’t visible to the gunners themselves.
According to the retrospective opinion of the artillery experts, however, it was “certainly not perfect, but its defects were of only secondary importance.” (3)
The first of these defects was an inefficient recuperation. The recuperator absorbs the energy of the recoil and returns the gun to its original position by a system of springs and hydraulics; its inefficiencies caused a “considerable loss of artillery power” especially during the Somme operations in 1916. By the end of the war, the springs had been replaced by “air recuperators.” (3)
The second and third defects were also remedied as the war progressed.
Its range – the distance over which it could deliver its shell – was deemed insufficient: at the beginning of the war, it had a range of 6500 yards – or well over 3 ½ miles (nearly six kms). (4) By the end of the war, its range had been extended by almost half as much again, to 9500 yards, nearly 5 ½ miles or 8.7 kms. (4) “Remarkable as these improvements were,” wrote the Canadian artillery expert Andrew McNaughton, “the German gun designers had an initial lead which we were never able to overtake, and at the end of the war their weapons still outranged ours on the average gun for gun by nearly 30 per cent.” (4)
The last of the defects was insufficient traverse.(2) Accurate aiming or “laying” of the gun requires both horizontal (traverse) and vertical (elevation) movement. “Elevation is always given by mechanism, traversing is sometimes carried out by mechanism and sometimes by hand.” (5)
Traverse by mechanism employed a traversing gear; traverse by hand meant (I think) pivoting the gun carriage upon its trail. Later in the war split trail (rather than single trail) carriages were developed which allowed more flexibility in traversing.(2)
(1) Barnes, Leslie. Canada’s Guns: An Illustrated History of Artillery. 1979. 66
(2) Handbook of the 18PR QF Gun. London: HMSO, 1913.
(2) Brooke, A.F. “The Evolution of Artillery in the Great War. III The Evolution of Artillery Equipment.” Journal of the Royal Artillery. 51 (April 1924): 38
(3) McNaughton, Andrew G.L. “The Development of Artillery in the Great War.” Canadian Defence Quarterly. January 1929: 160
(4) McNaughton. 161
(5) Handbook of the 18PR QF Gun. London: HMSO, 1915. Plate IX. 80.