One other thing, There is a certain efficiency improvement in some cartridges because of the cartridge shape.
The Efficiency is normally in ES and SDs being better/lower. Bench rest shooters believe that a short fat case is better because of better, more consistent powder burn in a short column of powder because of the Flame front .
It is hard to disprove because most of the bench rest cartridges are short and fat. They are also normally small capacity cartridges that burn fast burning powders.
The game we are in "Long distance and terminal energy" requires more of everything, barrel length,
bullet diameter, velocity, energy, High BC bullets, ETC. so powder efficiency is not a prime concern.
An Efficient cartridge is one that fills a certain need for distance, game, trajectory, energy at POI
and resistance to outside interferences(Like wind) the farther out we go the bigger the bullet, the more powder, the longer the barrel, the larger the case needs to be.
I own a 7 WSM because I had heard how efficient the Cartridge was. I also own a 7mm rem mag. both rifles have the same barrel length so I was interested in seeing what the WSM would do compared to the 7mm rem mag. I could never reach the advertised velocity of the WSM with reloads and the recommended powders available.
So I unloaded one of the factory rounds that would match the velocity of the 7mm RM with the same bullet weight and found 71 Grains of powder in the WSM (Way more than the powder weight possible in the 7mm RM with the same bullet weight. so Is the WSMs more efficient ? in my opinion NO. It does operate at a higher pressure than the 7mm rem mag though. But It is nice to have the same performance in a short action rifle.
Just more conversation about Efficiency.
J E CUSTOM