Jamie,
What you say with regard to one rifle not being a representative sample is true. I was simply using the info in the previous post as a data point.
Over the years, as our knowledge of ballistic science has improved, we have seen some significant changes in cartridge design. A long while ago, all cartridge cases were rimmed and pretty much straight walled.
Then came the bottle necked cartridges using smokeless powder.
It wasn't all that long after that that the first magnums came along. They had significant body taper and shallow shoulder angles. Just look at a .300 or .375 H&H case to see what I mean. It was thought that such a case design, which ruled the roost in long range competition, was ballistically superior. We now know that that is not the case. In fact, the severe taper and shallow shoulder angle is what is responsible for the fact that Holland & Holland put belts on their cases. The original purpose of those belts was to provide positive headspacing as the rims on other designs do.
Modern cartridge designs do not have nearly as much taper and are designed with sharp enough shoulders that the belt is not necessary. Yet, for generations a "magnum" was not a "magnum" without a belt.
Then, a while back, Ferris Pindell and Lou Palmisano (and Jim Stekl of Remington) discovered that a shorter, fatter cartridge case design was more efficient, and more accurate that the traditional longer, slimmer designs. Thus was the PPC and BR cartridge series born. And they, in particularly the PPC, have dominated benchrest competition ever since.
The new short magnums are the inevitable result of the development of the PPC and BR cartridges. What Winchester and Remington (with their SAUMs) have done is to adapt this ballistic development to the world of big game hunting and long range rifle competition. The new cartridges develop the same velocities and trajectories as the belted magnums using less powder. They are more efficient and inherently more accurate than the designs that preceded them, just as the PPC and BR are improvements on the previous top benchrest cartridges.
That a magnum cartridge must have a belt is fast becoming no longer the view of modern shooters. The belted design takes up space on the bolt face that can be used for a fatter cartridge design with more powder capacity or a shorter, fatter case that will give the advantages of magnum performance in a short action rifle. Short actions mean reduced weight and more stiffness.
Right now I own two rifles on belted magnums, a 7mm Remington and a .300 Winchester. Am I going to rush right out to buy the newer short magnum versions? Heck no! The older designs still suit my purposes admirably. However, if I were a long range target shooter, I surely would. Just a bit more accuracy can often spell the difference between victory and defeat in that arena.
Who knows what the future of cartridge design holds for us? Could it be something like this wildcat, the 6mm Thermos Bottle?
"The 6mm Thermos Bottle was designed by M.L. McPherson in 1999. It is based on shortened Lazzaroni Patriot case (or 416 Rigby). The purpose of this Thermos Bottle design was to make a fat and short cartridge, able to handle the heavy 115 grs VLD bullets for 1000-yard benchrest competition. From a 30 inch barrel, it generates approx 3000 fps." (courtesy of
www.reloadersnest.com )
One thing's for certain, tomorrow's cartridges will be improvements on what we have today. The only question will be whether or not an individual rifleman will feel the need for those improvements in his/her shooting. And that will be a matter of personal preference.