All parents are proud of their children — with good cause — but few cartridges have the brood of offspring that the .30-06 does, save perhaps the .375 H&H Magnum. Just think about the immediate children of the Springfield: the .270 Winchester, the .25-06 Remington, the .280 Remington, the .35 Whelen and the .338-06 A-Square, just to mention the commercially produced lineup.
There are those other children who’ve stayed out of the limelight (commercially, that is), which include the 6.5-06 and the twins, the .375 and .400 Whelen. I’ve read of wildcats as small as .22 caliber based on the ’06 case; well, I believe you get the point. Hell, even the .308 Winchester can trace its lineage back to the .30-06, so you’d call them cousins, but the .243…