The first battle of Ypres in 1914 marked the end of the "Old Contemptibles", the well experienced and trained British Army.    The Brit's had taken so many casualties that quickly trained men were the new army.  Gone were the days the Brits had time to dote over teaching rifle fire.  But one of the features of that battle were the results of an army trained tediously to use their rifles.  At the Battle of Gheluvelt on 29-30 October, 1914, the Germans made one last try to break the Brit line, but was clobbered so badly by British rifle fire the Germans thought they faced a line of hidden machine guns.  The Germans refer to the battle as "The Massacre of the Innocents".  By not breaching the line, World War One devolved into a line of trenches that cut all the way across Europe.  This video, by Stan the Gun Man,  illustrates the type of fire that pushed back the Germans, but multiply it by hundreds and include bullets that didn't miss their mark.