Weight of .303 round?????

[Karnak]

Originally posted by YUCCA
Any body ever wonder if like when a dogfight was happening in over a village or whatever if some citizens were hit my spent casings?

I've seen a photo of some British kids holding 20mm casings from the fighting in the BoB.  At least that is what it looked like and purported to be.

[Furball]

imagine being unlucky enough to be in a field below a b17 formation which is under attack

[frank3]

Over crowded areas (like over Holland) the (allied) fighters would usually fire a short burst before they dropped their tanks (so people could find cover)

Polite guys

[Mobius0077]

What I don't understand is why they were used at all in real life. Its like an aircraft BB gun. In AH I remember chasing a Bf109-G2 for about 15 mins in a Spit Mk V putting at least 100 .303 rounds (I was out of 20mm) into the main body of the plane and it smoked and lost a tail aileron but nothing else as far as I could tell.

[Leayme]

An airplane is a fragile thing and unlike AH in real life , rifle caliber ammo is a serious threat to aircraft and a piece of electrical system shot away, hydraulic line puctured or linkage bent can lead to a quick end, not to mention the rather fragile human being in control of the whole thing.

Rifle bullets that are deformed or ballistically intact have a nasty tendency to bounce and ricochet off of hard surfaces  and can be equally lethal after penetrating thru structures.

[Tony Williams]

But nonetheless all air forces discovered that rifle-calibre MGs were inadequately destructive and switched to larger calibres as a result, 20mm being the 'international standard' fighter armament in the last years of the war.

Tony Williams: Military gun and ammunition website and discussion forum

[Kurfürst]

The other trouble with the .303/7,62/7,92 ammo was that it`s structural damage making potential was negligable, and the round was completely incapable of of penetrating any pilot or fuel tank armor. Incendinary composition was low, and the only hope was to hit some control surface, the pilot or the engine from side angle.. it was not satisfactory by any means.
Whart is surprising that their ineffectivenessit was well discovered during the Spanish civil war, yet it took until 43/44 for most countries to replace them in the major fighter designs..

[Karnak]

Originally posted by Kurfürst
The other trouble with the .303/7,62/7,92 ammo was that it`s structural damage making potential was negligable, and the round was completely incapable of of penetrating any pilot or fuel tank armor. Incendinary composition was low, and the only hope was to hit some control surface, the pilot or the engine from side angle.. it was not satisfactory by any means.
Whart is surprising that their ineffectivenessit was well discovered during the Spanish civil war, yet it took until 43/44 for most countries to replace them in the major fighter designs..

True to a point.  They are inadequate against any armored aircraft (by which I mean Bf109E-4s and Spitfire Mk Ias from the BoB, not Il-2s) but in numbers they are fine against something like a Gladiator or A6M2.


I'm curious about your 43/44 claim though?  It seems to me that by 1940 the Germans, IJN and Armee l'Air had already gone to 20mm and the RAF knew it was going to.  By mid 1941 the RAF had gone to 20mm and the VVS was also going to 20mm.  The IJA didn't comit to to 20mm until 1944, true and the USN although planning on adopting the 20mm functionally did not during the war.  The USAAF never went to cannons, even the F-86 of the nascent USAF being armed with 12.7mm guns.

It seems to me that the majority of the combatants were using 20mm, backed up by machine guns of one size or another, from 1941 on.


The .303s retained on the Spitfire and Mosquito were a "In case the cannon jam like they did on the attempted instalations on the Spitfire Mk Ib." type of thing.  The .303 armed Spitfire Mk Va was only made as a backup in case the 20mm didn't pan out, and very few of those were made.  The Typhoon Mk Ia was armed with 12 .303s, but never entered production and for the same reason.

[Krusty]

"The .303s retained on the Spitfire and Mosquito were a "In case the cannon jam like they did on the attempted instalations on the Spitfire Mk Ib." type of thing. The .303 armed Spitfire Mk Va was only made as a backup in case the 20mm didn't pan out, and very few of those were made. The Typhoon Mk Ia was armed with 12 .303s, but never entered production and for the same reason."

Have to disagree with you there....

I know at least 1 report of a 109E pilot that said he got most of his kills with the 7mms. He didn't bother using the 20mms on fighters, because the MG/FF trajectory was poor.

I know some aces didn't want to use cannon in their spitfires (DB comes to mind), they prefered the power of the MGs.

MGs ***were*** effective, as evidenced by the way 50cal were in every succesful USAAF plane in the war, and they got the job DONE, and done WELL. When a P51 hit a target the target went down. When a P47 hit a target the target went POOF (so to speak). MGs are very potent. FYI: 109E and Spit1 (BOB) only had pilot armor. The plane itself was not armored. 109s were known to dive straight for the deck if they got a tail, because the pilot was literally sitting on his gas tank. While *HE* was protected from the rear, his plane was not.

The reason the RAF started putting in 20mms was because of the bombers attacking Britain. The rifle caliber just couldn't knock down the larger bombers. So the 20mm was needed. That's why the hurcMk2 has 4x20mm, it was primarily tasked with bomber attacks, while the less numerous spitfire would engage the fighter cover.

They had the universal wing for the spits, too. It could take 4x20mm, but it was decided not to. There was no reason for it. The bomber threat was gone after the BOB. So they stayed with MGs and then cannon.

MGs weren' t the backup. They were the primary. Once a pilot ran out of 20mm he didn't tuck tail and run (like in AH, lol!). He didn't bat an eye. His MGs were just as effective. Now when he ran out of THOSE he thought long and hard about egressing.

Typhoon was ground attack and high-speed interceptor. Not meant as a dogfighter. So even 12x303cal aren't as effective against bombers or hard targets as 4x20mm.

[Tony Williams]

Well, I have to disagree with you!  

For a start, you are conflating the .50 cal (12.7 mm) MGs with the rifle-calibre (.30": 7.6-7.9 mm) ones. There was a huge difference in power and effectiveness. The .50 cal remained effective (at least against fighters) throughout the war. The .30 cal did not.

This is an extract from 'Flying Guns – World War 2: Development of Aircraft Guns, Ammunition and Installations 1933-45' (a good book, by the way...). It is concerned with British ground tests of British .303 and German 7.92mm armour-piercing ammo against a Blenheim light bomber - not the toughest of targets:

"The test then changed to shooting at the rear of the long-suffering Bristol Blenheim at the same distance, involving penetrating the rear fuselage before reaching the 4 mm armour plate protecting the rear gunner, which was angled at 60º to the line of fire. The results in this case were reversed; 33% of the .303" rounds reached the armour and 6% penetrated it. In contrast, only 23% of the 7.92 mm bullets reached the armour, and just 1% penetrated. The British speculated that the degree of stability of the bullets (determined by the bullet design and the gun's rifling) might have accounted for these differences."

Even during the BoB, RAF pilots got fed up with hosing Luftwaffe bombers with .303s only to see them fly off home, despite their skins being riddled with .303-sized holes. And after that, planes got tougher...

The 20mm cannon was selected as the standard fighter armament by every major air force except the USAAF by the early 1940s. Those which needed to counter big, tough bombers (Germany and Japan) were moving up to 30mm by the end of the war.

Tony Williams: Military gun and ammunition website and discussion forum

[Krusty]

You agreed with me in part

The 20mm was developed for use against bombers mostly.

However the fact that they did not totally remove the MGs from fighters tells a lot about the usefulness of MGs. Whether 4x303 or 2x50cal, the majority of all spits had MGs throughout the war (4x20mm wasn't really needed, and the few in that configuration were the exception to the rule).

The planes that DO have 4x20mm are bomber interceptors or ground attack planes. They didn't dogfight so much.

Don't confuse "equipping 20mm" with "setting 20mm as the standard weapon".

[Tony Williams]

Originally posted by Krusty
You agreed with me in part

The 20mm was developed for use against bombers mostly.

However the fact that they did not totally remove the MGs from fighters tells a lot about the usefulness of MGs. Whether 4x303 or 2x50cal, the majority of all spits had MGs throughout the war (4x20mm wasn't really needed, and the few in that configuration were the exception to the rule).

The planes that DO have 4x20mm are bomber interceptors or ground attack planes. They didn't dogfight so much.

Don't confuse "equipping 20mm" with "setting 20mm as the standard weapon".

The primary purpose of fighters, pre-war, was to intercept bombers. Any fighter which had armament which was only useful against other fighters would have been a waste of resources. It was only the development of escorted bomber raids (which put the escort fighters in conflict with interceptors) which led to extensive fighter v fighter conflict.

So I would say that a good all-round fighter needed to be armed to deal with both bombers and fighters. One which was only effective against other fighters was specialised and rather limited.

The French were the first to make extensive use of 20mm cannon, and this practice was copied by the Germans (long before they had any heavy bombers to worry about). They retained the MGs primarily as back-up weapons, partly in case the cannon failed (reliability was not initially a strong point) but mainly because early drum-fed cannon installations had limited ammo capacity so soon ran out.

The RAF specified an all-cannon armament for new fighters being developed from the start of WW2. Existing designs, like the Spitfire and Hurricane, were modified to take cannon. Once the Hispano was in regular service, the Spitfire was the ONLY single-engined fighter made for the RAF which didn't have an all-cannon armament, and that was because the extra weight of four cannon had a poor effect on its performance and handling. And because two cannon were destructive enough, most of the time  (being about equal in this respect to six .50s). There is no question that the RAF regarded the 20mm cannon as its standard fighter armament - and was planning for that before WW2 even began.

Tony Williams: Military gun and ammunition website and discussion forum

[Kweassa]

You're picking a fight with the wrong guy Krusty

[Krusty]

Meh