British aircraft machine guns of WWII
| Type | Weight | Rate of Fire | Muzzle Velocity | Feed Type |
| Browning .303 | 23 lb | 1140 rpm | 2840 fps | Belt |
| Browning .50 | 61 lb | 750-800 rpm | 2900 fps | Belt |
| Browning .50 Heavy | 78 lb | 1100 rpm | 2900 fps | Belt |
| Lewis | 26 lb | 550 -1200 rpm* | 2450 fps | Drum usually 96 rounds |
| Vickers K (VGO) | 26 lb | 800 - 1200 rpm | 2400 fps | Drum usually 96 rounds |
* The Lewis gun's rate of fire would "accelerate" the longer the trigger was pressed. The Lewis gun was prone to more stoppages than the Vickers K gun, and those stoppages were harder to clear. This made the Vickers K much more popular with air gunners. The Vickers K was in widespread use by the RAF early in the war and it would have been rare for a Lewis to have been used in combat by the RAF. Meanwhile the Fleet Air Arm still retained the Lewis gun early in the war, but Vickers K guns were "obtained" whenever possible.
Non- aircraft machine guns for comparison
| Bren .303 | 23 lb | 500-520 rpm | 2440 fps | 30 round magazine |
| Vickers .303 | 33 lb without water | 450 rpm | 2440 fps | Belt |
| Vickers .50 | 63 lb without water | 500-600 rpm | 2540 fps | Belt |
| Besa 7.92mm | 48 lb | 450-850 rpm | Belt | |