Then you can pump your numbers into a calculator and find out that the kinetic energy values indicate that the HS should be (1.7?) times better then the 151. And look its nearly twice as good in my testing..so whats the problem.
Because Kinetic value is only part of the equation.
Then you have to consider the additional explosive content of the larger shell.
It should also be realized that typically the larger the shell, the higher proportion of explosive to total weight.
Additionally, the range factor comes into play that considers each shell types ballistic coefficent
Here's some data that might help you out.
1.)The US Army's 20mm High Explosive/Incindiary cannon shell used during WWII has the following characteristics.
Total Projectile Mass = 1565 grains
Explosive Mass = 165 grains of TNT
% Mass of Explosive = 10.54 %
Source: US Army's Small Arms Ammunition Pamphlet, 23-1 SSA. August 1968. Picktany Arsenal. Or alternatively, US Army Ammunition Data Sheets, Small Caliber Ammuntion. TM 43-0001
2.)The US Army's 30mm High Explosive/Incindiary cannon shell used during WWII has the following characteristics.
Total Projectile Mass = 2295 grains
Explosive Mass = 600 grains of TNT, plus 70 grains of RDX
% Mass of Explosive = 29.19 %
Source: US Army's Small Arms Ammunition Pamphlet, 23-1 SSA. August 1968. Picktany Arsenal. Or alternatively, US Army Ammunition Data Sheets, Small Caliber Ammuntion. TM 43-0001
(3.) The explosive yield of TNT is reported as 1080 kCalories / kilogram of mass, or as 4.10 kJoules/ gram of mass.
Source: Explosives, 4th Edition. By Rudolph Meyer. ISBN: 1-56081-266-4
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Vermillion
**MOL**, Men of Leisure
Carpe Jugulum
"Real Men fly Radials, Nancy Boys fly Spitfires"
[This message has been edited by Vermillion (edited 05-10-2000).]