Soren said:
Ahh but you are. Even in this post in your next statement you say exactly that! 4 x .303's are, in your estimation, equal to 2 x .50's (out to 120 m).
Yes in their own right they are, and coupled with the 2xHispano's they were very effective. But i wasnt suggesting 8x.303's vs 4x.50's !
So you are suggesting that somehow by being paired with 20mm they become more effective?
Soren said:
Why is it that when people compare the .50 Lightweight Aircraft M2 to other guns, they always choose the maxium RoF of the other gun, but the minimum for the M2?
As far as I remember, you mentioned the .303 to have an ROF of 1200rpm ! and the M2 950rpm.
My error - I should have looked up the RoF rather than rely on memory, where I rounded it to 1200 rpm.
Soren said:
The .50 cal round itself was about 4.2-4.6 times as destructive as the .303.
http://www.quarry.nildram.co.uk/WW2guneffect.htm
Tony William's uses momentum, rather than ke, to determine hitting power. Even he admits this is a somewhat arbitrary decision. While I would agree with him that ke is not entirely valid, I also think that momentum is not entirely valid either. Something in between makes more sense, as momentum relates to penetration but ke relates to shock effect and shrapnel/spalling effect. When I did my gun tables, I used the formula:
hitting power = 1/2 mass * velocity^1.6 (i.e raised to the 1.6 power)
This formula splits the difference between momentum and ke results almost exactly in the middle.
Furthermore, they relay the power at the muzzle, not the power at the hitting distance. As I showed before, the .303 velocity drops three times as fast as the .50 velocity for a given target distance.
Soren said:
Look at table 2 :GUN POWER AND EFFICIENCY.
Here the Browning .303 and 50 Browning M2 are listed as equal !
This table relates the weight of the gun (but not the ammo supply) to the power in the eariler table. Weight of the gun has nothing to do with effectiveness of the hits, so this table is of no real value.
Soren said:
Then take a look at table 3: FIGHTER FIREPOWER.
The Spit Mk.Vc with 4x.303's + 2xHispano's; Armament power= 480.
The Spit Mk.XIV.E with 2x50's + 2xHispano's; Armament power= 520.
They are very close !
Again, that table is based upon the power figures he used earlier, which use muzzle momentum, not really a valid comparison at all.
The problem with the .303's is that by the time they've pentrated the skin they have little power left. They tumble easily too and don't have enough mass to penetrate well even with a perpendicular strike, a strike while oriented sideways will do little damage to most components and almost none to structure. The .50's are large enough and have enough mass/energy to penetrate the skin and do damage to anything they hit inside, even if they tumble - in fact usually they would do more damage if they tumble.
Soren said:
All im trying to say is that the 4x.303's + 2xHispano's armament wasnt ineffective, and more or less on par with the 2x.50's + 2xHispano's armament against Fighters.
Also the lower weight of the Browning .303 gun was an advantage of its own.
Well, I really don't think this is true. By mid war, against the FW190 the .303's were nearly useless. The combination of weak initial hitting power, poor ballistics, very poor hitting power at range, and small payload all added up to an ineffective round. And it was virtually impossible to make an API round in that caliber.
The only reason the British kept using the .303 was because they had to import the .50 BMG, but made their own .303 Brownings, along with the issues of adding .50 ammo to their supply chains. They were setup to support the .303, not the .50.
The .50 BMG was a very big improvement on the .303. The gap between .303 and .50 is much larger than the gap between .50 and 20mm.
Weighing less is only an advantage if the gun is still effective. The Soviet UBK Berezin was an example of a gun that was far more "efficient" than the .50 because it had the same hitting power but weighted a lot less (and had better RoF).
=S=
Lunatic