WW2: why so many .303 guns?
Cunning Artificer
Join Date: Jun 2001
Location: The spiritual home of DeHavilland
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Ignition Override,
The 7.62mm bullet is exactly 0.30 inches in diameter as are the American .30-30, .308 and the British .303 bullets. The second and third digits of the latter two calibers serve to indicate the size of the lands in the barrel of the weapons that fire them - an even number of .004" in the former and an odd number of .003" in the latter. The current 7.62 mm NATO is in fact exactly the same round as .308 Winchester.
A 20mm cannon shell is somewhat less than one inch as there are 25.4mm to the inch.
A .50 calibre bullet is not only thicker but also one third longer than a .303/.308 giving it 3.7 times the mass of the smaller bullet.
Moving up to 20mm cannon takes the projectile mass up to five times that of the .50 bullet and almost eighteen times the mass of the .303 bullet. It is easy to see why the larger calibre weapons were preferred by the fighter piots and air gunners. Typical engagement ranges were no more than 150 yards in most cases, its the weight of fire that counts rather than the ballistics.
The best indicator of hits is the bits of metal flying off the enemy aircraft...
...and size really does matter!!
The 7.62mm bullet is exactly 0.30 inches in diameter as are the American .30-30, .308 and the British .303 bullets. The second and third digits of the latter two calibers serve to indicate the size of the lands in the barrel of the weapons that fire them - an even number of .004" in the former and an odd number of .003" in the latter. The current 7.62 mm NATO is in fact exactly the same round as .308 Winchester.
A 20mm cannon shell is somewhat less than one inch as there are 25.4mm to the inch.
A .50 calibre bullet is not only thicker but also one third longer than a .303/.308 giving it 3.7 times the mass of the smaller bullet.
Moving up to 20mm cannon takes the projectile mass up to five times that of the .50 bullet and almost eighteen times the mass of the .303 bullet. It is easy to see why the larger calibre weapons were preferred by the fighter piots and air gunners. Typical engagement ranges were no more than 150 yards in most cases, its the weight of fire that counts rather than the ballistics.
The best indicator of hits is the bits of metal flying off the enemy aircraft...
...and size really does matter!!
Blacksheep,
You are obviously a highly technical individual, a couple of questions,
1. Lands....are these the raised portions of the rifling (ie the opposite of the groove)? There appears to be no indication of the amount of grooves or is six accepted as the standard?
2. Why is rifling appear by convention to impart a right hand spin although I do believe that some Chinese and Polish weaponds have a left hand spin but these are very much a rareity.
You are obviously a highly technical individual, a couple of questions,
1. Lands....are these the raised portions of the rifling (ie the opposite of the groove)? There appears to be no indication of the amount of grooves or is six accepted as the standard?
2. Why is rifling appear by convention to impart a right hand spin although I do believe that some Chinese and Polish weaponds have a left hand spin but these are very much a rareity.
Join Date: Sep 2000
Location: The scouse end of the M62
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One for the techies, lots of information here, I haven't had time to read it all ....
http://www.geocities.com/CapeCanaver...n/fgun-pe.html
Ignition Overide, here is some other info from the web, so yes, the Spits and Hurricanes did fire other rounds than just standard ball rounds ....
"The B. Mk VI 'De Wilde' incendiary (named after the original Belgian inventor but in fact completely redesigned by Major Dixon), which contained 0.5 grams of SR 365 (a composition including barium nitrate which ignited on impact with the target).
The 'De Wilde' bullets were first issued in June 1940 and tested operationally in the air battles over Dunkirk. Their improved effectiveness, coupled with the fact that the flash on impact indicated that the shooting was on target, was much appreciated by the fighter pilots. It was at first in short supply, and the initial RAF fighter loading was three guns loaded with ball, two with AP, two with Mk IV incendiary tracer and one with Mk VI incendiary. Another source for the Battle of Britain armament gives four guns with ball, two with AP and two with incendiaries (presumably Mk VI) with four of the last 25 rounds being tracer (presumably Mk IV incendiary/tracer) to tell the pilot he was running out of ammunition. It is not clear why ball was used at all; presumably there was a shortage of the more effective loadings. (By 1942 the standard loading for fixed .303s was half loaded with AP and half with incendiary.)"
http://www.geocities.com/CapeCanaver...n/fgun-pe.html
Ignition Overide, here is some other info from the web, so yes, the Spits and Hurricanes did fire other rounds than just standard ball rounds ....
"The B. Mk VI 'De Wilde' incendiary (named after the original Belgian inventor but in fact completely redesigned by Major Dixon), which contained 0.5 grams of SR 365 (a composition including barium nitrate which ignited on impact with the target).
The 'De Wilde' bullets were first issued in June 1940 and tested operationally in the air battles over Dunkirk. Their improved effectiveness, coupled with the fact that the flash on impact indicated that the shooting was on target, was much appreciated by the fighter pilots. It was at first in short supply, and the initial RAF fighter loading was three guns loaded with ball, two with AP, two with Mk IV incendiary tracer and one with Mk VI incendiary. Another source for the Battle of Britain armament gives four guns with ball, two with AP and two with incendiaries (presumably Mk VI) with four of the last 25 rounds being tracer (presumably Mk IV incendiary/tracer) to tell the pilot he was running out of ammunition. It is not clear why ball was used at all; presumably there was a shortage of the more effective loadings. (By 1942 the standard loading for fixed .303s was half loaded with AP and half with incendiary.)"
Last edited by Danza; 23rd Mar 2004 at 15:55.
