Comparison of .50 cal Colts with .303 Brownings

[SCTusk]

Not sure how interesting this might be to anyone else, being unfamiliar with the 50 cals I was suprised at the difference. The data comes from a book by Wing Commander H.R. Allen DFC titled 'Who Won the Battle of Britain', which suggests that but for an Air Ministry oversight both the Spitfire and Hurricane could have been fitted with a battery of four .50 calibre Colts prior to the Battle of Britain. Apparently they were available at the time but as to whether they could have been physically fitted, quite possibly but he doesn't elaborate.

Anyhoo, you might not think there'd be that much difference between a third of an inch and half an inch (the wife says yes and keep using the cream) but check this out: (the comparison assumes 4 x .50 cals carried against 8 .303's)

Calibre   Bullet Weight (grains) Muzzle Velocity (fps)  Number of Guns (per a/c)  Max Rate of Fire (per gun per minute)    Total Energy Delivered in 1 minute (ft/ilbs)            Relative Range

0.50 (Mk2)        710                         2,900                                    4                                     850                                            45,316,384                                        2
0.303 (MkVII)    174                         2,240                                    8                                   1,350                                            21,047,040                                        1

The author adds "a battery of four 0.5-in Colts would be devastating compared with eight 0.303-in Brownings" and "the former was effective over twice the range of the latter". He also adds "The energy advantage possessed by the Colt battery over the Brownings is sufficient in one minute's firing to lift a locomotive weighing 100 tons to a height of 100 ft. The effect of a hit on an enemy aircraft by a Colt as opposed to a Browning would be seven times more damaging."

He goes on to suggest that if the Air Staff had done their homework and opted for the Colts, the Battle of Britain may have been over so quickly as to not have merited the name or assumed the historical significance which the closeness of the conflict (and apparent near defeat of the RAF) has lent it.

[Saxman]

He's talking about the US .50cal M2, right? Does he not realize that was ALSO a Browning?

[Charge]

Hmm, energy is "delivered" only if it hits some place it can deliver the energy to. If the projectile whips through aircraft it uses only a fraction of its energy and is not much of use so in a away that is also a form of over-penetration. A projectile of less energy may be more better suited for certain uses if it tumbles more easily and is able to release most if not all of its energy on a/c structures and break them rather than just puncturing neat holes in them.

So the actual power delivered to target depends on hit probability i.e. number of guns and ROF vs. the damage per projectile and optimal firing range. In that sense the .303 starts to make sense.

I'd say that against lightly defended German bombers the .303s were very good weapons as you had to go, and could go, close and get a very high percentage of hits and good "energy transfer" to bomber and even if there was only considerably light damage to bombers they often could not get home anyway.

While in numbers wise the .50 looks like a good idea the actual effect it would have had in BoB is debatable, IMO.

-C+

[Karnak]

As I understand it, the British decided that the HMG was only a stopgap solution and so focused efforts on getting 20mm cannons in service as the next step of fighter primary armament.

[Squire]

Several points.

* The Luftwaffe armed ALL of its 1940 combat a/c with 30 cal machine guns: He-111, Do-17, Ju-88, Bf 109, Bf 110, Ju 87 all had them. Presumably because they saw a use for them. Yes, some had the 20mm MG-FF cannon as well, which was a slow ROF and low velocity weapon. However the 7.92mm MG was the *only* armament on its bomber fleet. Everybody seems to forget that and talk as if the RAF was the only air force in the world using 30 cal mgs on their a/c in 1940.

*USAAC fighters in 1940 were not armed "50 caliber MGs" entirely either. The P-40B and P-36 had 4 x 30 cal and only 2 x 50s. Both in service at the time of Pearl Harbor almost a year and a half after the BoB was over.

*The BoB was not fought in 1944. It was fought in 1940. Most air forces fighter planes were armed either entirely or in part with 30 cal machine guns. Check the data for the IJAAF, Reggio Aereonatica and Soviet 1940 era fighters too. They were not armed with multiple batteries of 20mm cannons and heavy MGs.

*Its always easy with 20-20 hindsight to sit back after the fact and wax about how this or that plane, ship, army unit, "could have should have might have wanted to have" X, Y, Z weapon or whatever. History never unfolds like that.

...All that said, yes, its true that they would have been better off with 12.7s. They would not have been the only ones. The heavy round would have done a better job of boring through the self sealing fuel tanks of the LW bombers. The early IJ a/c had no self sealing tanks or crew armor which is why the went up like roman candles when hit by incindiary rounds. Thats what the British planners were looking at in the 1930s, enemy bombers with older style fuel tanks that would ignite when hit.

[RTHolmes]

interesting





... if you like this kind of thing

[FLS]

SCTusk just comparing the diameter difference doesn't begin to compare the rounds. For example the .22 rimfire and .223 are essentially the same diameter. The .22 and .223 are on the right end. The .303 would be in the center of the picture if it was included. The .50 is on the left.

[Jabberwock]

Not sure how interesting this might be to anyone else, being unfamiliar with the 50 cals I was suprised at the difference. The data comes from a book by Wing Commander H.R. Allen DFC titled 'Who Won the Battle of Britain', which suggests that but for an Air Ministry oversight both the Spitfire and Hurricane could have been fitted with a battery of four .50 calibre Colts prior to the Battle of Britain. Apparently they were available at the time but as to whether they could have been physically fitted, quite possibly but he doesn't elaborate.

Anyhoo, you might not think there'd be that much difference between a third of an inch and half an inch (the wife says yes and keep using the cream) but check this out: (the comparison assumes 4 x .50 cals carried against 8 .303's)

Calibre   Bullet Weight (grains) Muzzle Velocity (fps)  Number of Guns (per a/c)  Max Rate of Fire (per gun per minute)    Total Energy Delivered in 1 minute (ft/ilbs)            Relative Range

0.50 (Mk2)        710                         2,900                                    4                                     850                                            45,316,384                                        2
0.303 (MkVII)    174                         2,240                                    8                                   1,350                                            21,047,040                                        1

The author adds "a battery of four 0.5-in Colts would be devastating compared with eight 0.303-in Brownings" and "the former was effective over twice the range of the latter". He also adds "The energy advantage possessed by the Colt battery over the Brownings is sufficient in one minute's firing to lift a locomotive weighing 100 tons to a height of 100 ft. The effect of a hit on an enemy aircraft by a Colt as opposed to a Browning would be seven times more damaging."

He goes on to suggest that if the Air Staff had done their homework and opted for the Colts, the Battle of Britain may have been over so quickly as to not have merited the name or assumed the historical significance which the closeness of the conflict (and apparent near defeat of the RAF) has lent it.

Mr Allen seems understate the case for the .303 and slightly overstate the case for the .50. In particular, he bases his data for the 'Colt' on the pre WWI Mk VIII ammunition, instead of the more usual Mk VIIZ/Mk VIII ammunition.

A couple of observations:

The MV for RAF .303 ammunition is either 2465 fps (Mk VII 'De wilde') or 2520 fps (MkVIII), not 2240 fps as stated.

The post WWI manufactured Mk VIIZ rounds and the Mk VIII round both weigh 175 grains, not 174 grains (an admittedly marginal difference).

His RoF figures are based on the 'Star' modification that RAF Brownings received early during the war, upping their RoF from 1150 to 1350 rpm. Some squadrons did not adopt this modification though, preferring the slightly longer trigger time.

The MV on the M2 Browning is typically cited as 2,905 fps, but the weight of the round is more like 670 grains, rather than the 710 cited.

The RAF decided, after trialing two .50s (the M2 and the Vickers) that the advantage they offered was not sufficient over the .303 and instead opted for the 20mm as the next step in aircraft armament for fighters.

As for arguing that "the Battle of Britain may have been over so quickly as to not have merited the name or assumed the historical significance which the closeness of the conflict (and apparent near defeat of the RAF) has lent it", this has a patent edge of silliness to it. Regardless of the armament of the Hurricane and Spitfire, they managed to down close to 2,000 German aircraft in a matter of 12 weeks. Heavier armament may have brought down more bombers, or perhaps not, its hard to argue. 13.2 mm armed Belgian Hurricanes didn't do appreciably better than RAF .303 armed Hurricanes.

[NOT]

SCTusk just comparing the diameter difference doesn't begin to compare the rounds. For example the .22 rimfire and .223 are essentially the same diameter. The .22 and .223 are on the right end. The .303 would be in the center of the picture if it was included. The .50 is on the left.

(Image removed from quote.)

My guess is , from R-L: .22    .223(as stated)   7.62x39    .30-06, or .308     300win mag??      .50





NOT

[SmokinLoon]

My guess is , from R-L: .22    .223(as stated)   7.62x39    .30-06, or .308     300win mag??      .50

NOT

R-L: .22LR (rimfire), .223 Remington (5.56 NATO), 7.62x39 Soviet, .308 Winchester (7.62 NATO), .338 Winchester Magnum (note the larger than .308 caliber bullet), and .50 BMG.

[Scherf]

Weren't the Spit and the Hurri both designed to be "eight-gun fighters"? I thought the whole point was that the Brits had looked at the kind of bombers which interceptors would need to attack, estimated the weight of fire required to knock same down, estimated the likely length of burst which could be put on the target, then figured out how many guns were required. Standard aircraft gun for the Brits at the time was .303, so...

[Ack-Ack]

While in numbers wise the .50 looks like a good idea the actual effect it would have had in BoB is debatable, IMO.

-C+

Especially since the RAF was using obsolete fighter tactics and formations, it really is debatable whether or not an increased in fire power would have changed anything significantly as the writer suggests.

ack-ack

[BaDkaRmA158Th]

.303 was ment for shooting deer and other large game. But was used on large metal airplanes instead.

.50cal was made to shoot airplanes and lightly armored object, and was used for that.


simple. One is effective for air to air combat, the other is not.

[Squire]

"other large game"

http://www.asisbiz.com/il2/He-111/He-111H-KG26-(1H+JA)/images/1-He-111H-KG26-(1H+JA)-WNr5449-shot-down-Scotland-Oct-28-1939-01.jpg

...would look fine on a wall mount but getting it home on the back of the truck might be tricky.   

[Ghosth]

.50's do deliver a lot more energy to target, but the biggest single advantage they bring is range.

.303's do fine at 150 - 200 yards, those 8 .303's rip wings off up close at convergence.
.50's do the same thing at double the effective range.