.303 v 0.50 Browninigs

I have often wondered why the RAF used .303 rather than the .50 cal. Both made by Browning, was it a lack of ammo supply at that time of the war?
The Hurricane wing could easly fit .50 Cal, in the Spit it could be a squeeze, but the Mustang with a similar cord wing managed it. And the MkV spit managed to fit cannons, not sure if it was the same wing as the earlier ones?
But if you can fit cannons you should easly fit .50’s.
Would having .50 fitted to Hurricanes made a difference in the BoB?
I think it would have made a huge difference.

So we’re just going to discount the Spitfire “E” wing, which was fitted with a single 20mm cannon and a single .50 Browning alongside it?

I’ve heard it said that the wing flex on a turning Spitfire made the Brownings in the outer bays of questionable value anyway – although that may be giving the average pilot’s shooting ability a little too much credit! I guess the trade-off for the M2 is fewer, heavier rounds vs. extended range and hitting power. Again, it comes down to the bloke on the end of the trigger; the longer effective range might encourage the average Joe not to get in close, thus accuracy plummets. In bomber turrets, however, the further away you keep the enemy, the better! Hence it’s a shame how long the Rose turret was delayed. One other attraction of the .303 was that the round was used absolutely everywhere, so no need for specialist supplies (less of an issue on home soil, granted).

A question which occurred to me, not neccessarily in light of 50-cal v 0.303 – what was the barrel life on these weapons? Presumably not very long if they were getting 300 rounds or more through them on a regular basis? My only (very limited) experience was with the C9 Minimi, where IIRC the recommended barrel life seemed distressingly short. On the bright side, it was dead easy to change – apparently not the case on the .303 where you basically need to dismantle the entire weapon. Firing them is all very well, but some poor bloke’s going to have 12 lots of 8x.303’s to service at the end of the day.

Although moving away from the Battle of Britain period, it is worth pointing out that in what we would call the middle war years, 1942-43, the US was rapidly building up its own armed forces and the 0.5 Browning was simply not available in large enough numbers to fully equip all British needs as well. Adequate numbers were not available until 1944, which is when they start to appear in British-built aircraft in any significant numbers. Whatever may have been the opinion in early 1941, from then on the increased armour on enemy aircraft made the superior penetration of the larger bullet obvious enough, but it was too late for any production changes on the UK lines, given that the superior 20mm cannon was available.

Leigh-Mallory, when he took over from Dowding, moved heaven and earth to get the .5″ accepted, but the Air Ministry steadfastly refused to consider it, because they felt that, given the general pilot’s inability to cope with deflection shooting, it was better to have four fast-firing guns than two slower-firing examples, since it gave a better chance of hitting, and disabling the enemy pilot, who rarely had side armour. They’d also found that the .5″ was no better than the .303″ at penetrating German armour, in a straight-behind shot.
When the gyro gunsight became available, the Air Ministry found that it enabled pilots to hit what they were aiming at, so they relented, which is why the E wing came into use in 1944.

There is about a x3 weight penalty for the ammunition alone, plus the additional weight of the gun.
:rolleyes:

Comparative weapons trials in the early thirties (when it was clear that replacement weapons were needed) showed little difference between the damage caused by 0.303 and 0.5 machine guns. It was therefore decided to standardise on the US Colt Browning, although modified from 0.3 to 0.303 which allowed for the use of large stocks of existing ammunition, and look to the 20mm cannon for the next following generation. There was no value seen in going for the 0.5 in between these two.

With the benefits of hindsight, these trials did not foresee the increase in use of stressed-skin structures and even light aircrew armour, although it is a moot point whether the decision would have been any different if it had. Given the number of German aircraft shot down by 8×0.303, it is difficult to imagine any “huge” difference from the adoption of a smaller number of 0.5 guns with less ammunition per gun, as would have been necessary to retain similar weights. Some difference yes, but we did win anyway. The Spitfire was only able to take four 0.5s: whether the design would have been significantly different had (say) 6×0.5 been required is a good question – but then it might have been different had more than 4×0.303 been the original design criteria.