A Machine Gun Company was attached to each Infantry Brigade and their subsequent Division.
| Brigade attached to: | 49th Brigade |
| Division attached to: | 16th (Irish) Division |
| Formed from the Machine Gun Sections of: | 7th Bn. Royal Inniskilling Fusiliers 8th Bn. Royal Inniskilling Fusiliers 7th Bn. Royal Irish Fusiliers 8th Bn. Royal Irish Fusiliers |
The 49th M.G. Coy. disembarked at le Havre on 26 April 1916 and joined the 49th Brigade on 29 April 1916. It may have absorbed machine gunners from the Machine Gun Sections of the listed infantry battalions.
As a unit of the 16th (Irish) Division during this period, it may have taken part in the following battles and engagements.
| 1916 | |
| 27 and 29 April | German Gas Attacks, Hulloch Front [I Corps, First Army]. |
| BATTLES OF THE SOMME | |
| 03 to 06 September | Battle of Guillemont (On 03 September, 47th Bde; on 04 September, 47th and 48th Bdes; and on 05 September, 16th Div.) [XIV Corps, Fourth Army]. |
| 09 September | Battle of Ginchy [XIV Corps, Fourth Army]. |
| 1917 | |
| 07 to 09 June | Battle of Messines [IX Corps, Second Army]. |
| 07 June | Capture of Wytschaete. |
| BATTLES OF YPRES | |
| 31 July to 02 August | Battle of Pilckem Ridges [In Reserve, XIX Corps, Fifth Army]. |
| 16 to 18 August | Battle of Langemarck [XIX Corps, Fifth Army]. |
| 20 November | Attack north of Bullecourt [VI Corps, Third Army]. |
By 09 March 1918, it was amalgamated with the 47th, 48th, and 269th Machine Gun Companies to form No. 16 Battalion, Machine Gun Corps.
