 As a result, it was prohibited from general use with rifles and light machine guns except when low flash was important and in emergencies As a consequence of the official prohibition, ordnance personnel reported that every man that could get his hands on Mk VIIIz ammunition promptly used it in his own rifle.Tracer and armour-piercing cartridges were introduced during 1915, with explosive Pomeroy bullets introduced as the Mark VII.Y in 1916.Several incendiaries were privately developed from 1914 to counter the Zeppelin threat but none were approved until the Brock design late in 1916 as BIK Mark VII.K Wing Cmdr.