All of this really astounds me. Warren Page had a 7 mm Mashburn in 1952 that would drive a 175 gr bullet at 3000+ within 65K pressures. His did then and mine does now. I have 2, one has a 1:8 twist barrel on it. The other a standard 1:9.5. Either will shoot/kill about any kind of game up to about 1200 lbs to as far as I what to try the shot.
Reinventing the wheel I guess, just because you can.
Aside from being a factory round, the 7mm SPC has several of the present-day touches that make some newer cartridges tend to shoot more accurately, including:
1) A shorter powder column, which tends to result in more consistent pressures and hence muzzle velocities.
2) A 30-degree shoulder, which on shorter fatter cartridges from the 6mm PPC on up tends to result in more consistent muzzle velocities.
3) A parallel throat, just barely above bullet diameter, which tends to keep bullets straighter as they move from the case neck to the rifling.
The first two have been demonstrated many times in piezo pressure labs. The third has been demonstrated many times on targets.
This doesn't mean the average hunter should rush out and buy a 7mm PRC when they already have a good 7mm magnum (even one with a belt). However, it does mean that for certain purposes sheer muzzle velocity is not everything, even though that's still what many hunters believe.
One other "advantage" for any 7mm magnum, even older ones, is today's powders, many of which are far less temperature sensitive, and include a decoppering agent. These tend to produce more consistent accuracy over a range of shooting conditions. I know this partly because my present 7mm magnum is the "old" belted Remington, though chambered in one of the new "affordable" rifles that many traditional hunters love to hate, a Mauser M18. But it performs best with some newer powders like those described above--and also with some newer bullets.
