 Franks planned to neutralise German guns within 9 @,@ 000 yards ( 8 @,@ 200 m ) of the attack front . On the flanks of the British attack front of 17 @,@ 000 yards ( 16 @,@ 000 m ) , 169 German guns had been located , for which 42 British guns ( 25 percent of the German total ) were set aside . The 299 German guns in the path of the attack were each to be engaged by a British gun , a formula which required 341 British guns and howitzers to be reserved for counter @-@ battery fire . Every 45 yards ( 41 m ) of front had a medium or heavy howitzer for bombardment , which required 378 guns , with 38 super @-@ heavy guns and howitzers ( 5 percent ) deployed with the field artillery that was due to fire the creeping and standing barrages . Franks devised a bombardment timetable and added arrangements for a massed machine @-@ gun barrage . The 756 medium and heavy guns and howitzers were organised in forty groups and the 1 @,@ 510 field guns and howitzers in sixty @-@ four field artillery brigades within the attacking divisions and thirty @-@ three Army field artillery brigades , divided among the three attacking corps . Ammunition weighing 144 @,@ 000 long tons ( 146 @,@ 000 t ) was delivered with 1 @,@ 000 shells for each 18 @-@ pounder , 750 shells per 4 @.@ 5 @-@ inch howitzer , 500 rounds for each medium and heavy piece and another 120 @,@ 000 gas and 60 @,@ 000 smoke shells for the 18 @-@ pounder field guns . 
