| Cat. No. | Introduction | Obsolescent | Obsolete | Remarks |
| Section C.1 7.J.1166 |
L. of C. C.1027 270/MG/132 18th January 1945 |
L. of C. C.2630 270/MG/132 12th February 1946 |
L. of C. C.3375 270/Vocab/428 10th November 1947 |
Aircraft gun, with spade grip |
| Length of gun overall with flash eliminator | 3 ft. 4 in. |
| Length of barrel | 1 ft. 8 in. |
| Weight of gun (approx). (i) Mk. I, No. 1 gun (ii) Mk. I, No. 2 gun |
19.75 lb. 20 lb. |
| Rifling (i) Type (ii) Twist (iii) Number of grooves |
Left hand 1 in 10 in. 5 |
| Ammunition used | All types of Mk. VII S.A.A. |
| Method of feed | Magazine |
| Capacity of magazine | (i) 60 rounds (ii) 100 rounds |
| Speed of fire (approx.) (i) Mk. I, No. 1 gun (ii) Mk. I, No. 2 gun (iii) Mk. I, No. 3 gun (iv) Mk. I, No. 4 gun |
950 rounds per min. 950 rounds per min. 950 rounds per min. 700 rounds per min. |
| Marks on the gun (i) On the side of the breech casing (ii) On the barrel (iii) On the breech block (iv) On various components |
Nature, mark and number of the gun Proof mark, Calibre, Year of manufacture (last two figures), Number of the barrel Number of the breech block Viewer's marks, Broad arrow, Maker's trade mark |
| Sights | Separate store |
| Mounting (i) Air service (ii) Ground service |
Turret or free installations Tripod |
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| (Source: AWM, [s.d.]d) |
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| (Source: AWM, [s.d.]e) |
However, an ambitious young officer in the form of David Stirling formed the Special Air Service and he found that the GO No. 1 gun was an ideal weapon for the types of missions which they would be undertaking. The high rate of fire made it so the SAS troopers would be able to get as many bullets into the target without having to stay on the ground longer than necessary. The SAS mounted the guns on their jeeps usually in pairs with two at the front and two at the back and then a single piece was sometimes mounted on the drivers side wing so the driver could get provide additional support as necessary.
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| (Source: Poston, 1942a) | (Source: Keating, 1943a) | (Source: Keating, 1943b) | (Source: Currey, 1943a) | (Source: Hewitt, 1944a) |
The Long Range Desert Group used the GO No. 1 in the same manner as the SAS.
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| (Source: Graham, 1942c) | (Source: Lawson, 1942a) |
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