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Originally Posted by dave99
I am both interested and confused by your method. Keep in mind that I really don’t know much about this stuff... :
Dividing KE at a fixed distance by the initial charge weight and comparing different cartridges this way looks like an interesting way to quantify efficiency.
The higher the quotient of KE / powder weight, the more efficient the cartridge is with respect to creating KE from powder burn. (Assuming that the combustion of powder x and powder y release equivalent energy- which I believe is probably false).
For one of my rifles 6.5cm with 24” barrel, 41.0 grains delivers 1752 ft-lbs at 300 yds. 1752/41 = 42.7. My best 30.06 load gets me 2130/57 = 37.3. So relatively poor compared to the 6.5cm.
According to your math, the number one performer in terms of efficiency is the .300 Win at 32.4.
Wouldn’t the lower values mean that the cartridge is inefficient at creating KE through powder burn? In other words, wouldn’t the 308 be your most efficient, followed by 30.06? With the .300 Win being least efficient?
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KE is a result of weight and motion or velocity. so the 300 Win mag wins. It delivers much more energy to its destination than a .308 or a 30-06.
A 30-06 is efficient , until it has to go to work and deliver a substantially greater amount of energy,- then the 300 Win takes over. The .308 Win even more lacking than the -06. The governing body's are Chamber pressure and case capacities. A smaller amount of powder used in a small cartridge case does not necessarily make it efficient when it comes delivering High energy bullets. They get super high velocity with their lighter bullets, but not much energy. Hope this makes sense. lol