I'm glad you asked. You see, 7mm is the optimum diameter for rifle cartridges. 7mm rounds give a 20% advantage in ballistic performance for any given level of recoil over 7.62mm rounds, because they have a far superior ballistic coefficient. And they can retain their energy at much longer ranges than 6.5 or 5.something rounds, while also delivering more kinetic energy to the target at any range. For example, the 7x43mm .280 British retained more energy and penetrating ability at range than 7.62x51mm NATO, and was also more accurate and had a flatter trajectory.
So bottom line, 7 mil beats out 7.62, 5.56, and other more exotic ammo because it can retain its energy in flight while loosing it when it hits the target? Does this carry over to different ammo types within the 7mm family(hollow point, jacketed, etc.)? Also, what is the source of this information, if you don't mind me asking?
Thank you so much for your prompt response. I greatly appreciate your input and explanation.
Basically, yes. What it boils down to is that 7mm diameters will bring one closer to a Sears-Haak body than 7.62 or above, while retaining more energy than smaller rounds. Yes. It's a function of the dimensions of the bullet, not the composition thereof. Sources are varied, but here's a few; [link], [link] (data on the .280 British) and the Wiki page for .280 British will offer some interesting info as well. A lot of it is actually just math done with ballistics calculators though.