| Cat. No. | Introduction | Obsolescent | Obsolete | Remarks |
| Section C.2 B.M.0165 B.M.0166 |
L. of C. A.7771 70/MG/159 15th May 1930 |
L. of C. A.9478 70/MG/198 17th August 1934 |
L. of C. C.2022 57/SA/1385 24th August 1944 |
With L.H. or R.H. feed blocks. Tank Pattern. Converted from Mk. I |
List of changes A 9478, GUNS, MACHINE, VICKERS .303-IN., Mk. IV B, - With No. 3 steam tube and Mk. I* steam tube keeper
The Mk IV A and Mk IV B Vickers MGs were, alongside the 3-Pounder, the only armament that the Royal Tank Corps had fitted to its Tanks. These were eventually replaced by the Mk. VI, Mk. VI* and Mk. VII, but did co-exist with those for some time. All A.F.V. Vickers MGs were eventually declared obsolete in 1944 when they were completely replaced by the Besa and Browning MGs.
The table below provides a small amount of manufacturing data towards the end of the Mk IV A and Mk IV B life and is an indication of the numbers concerned when compared to data on the Mk. VI, Mk. VI* and Mk. VII.
| Date | Item | Maker | Quantity and Other Details |
| 01.07.1935 | Modifications to Vickers Mk IV | Enfield | 2 |
| 16.01.1936 | Vickers Mk IV A and B repair | Enfield | 30 |
| 21.08.1940 | Vickers Mk IV | Enfield | 27 |
The last entry indicates a new production; however, this may be a transcription error in the primary or secondary source as the Mk IV A and B were obsolescent by this time - it would be more feasible to read as the Mk VI.