Caliber restriction is what compelled shooters to develop the 6mm in short range Benchrest.
Back in the day, when the 22 cal ruled Benchrest, I suppose the powers that be decided the sport needed a class that banned the 22, and made Sporter 23 caliber and above.The invention of the 6PPC showed that a 6mm could agg just as well, possibly better than a 22.
I suppose this was also back when Benchrest wanted to keep some tie, though vague, to what the rest of the shooting world recognized as a rifle.
The 22 didn't completely disappear, but as more and more shooters found out that they could build a 6mm to compete in all three classes, it was sure put on life support.
So perhaps if the NBRSA stated that Sporter could be anything but a 6mm, would we then see a resurgence in perhaps a larger caliber, or maybe even the 22 again. (Back to square one with that).
I did not mention the 30 cal because it already has it's following in Varmint for Score.
I think the NBRSA will always need a class that allows one Rifle to be used in all three Bag Gun Classes, (and be competitive), which is what many shooters do. For years, it was the Sporter chambered in 6PPC, which evolved into nothing but a 6mm Light Varmint. Now, it is Light Varmint, since if you do take advantage of all of the rules in Sporter, it is rendered illegal in LV and HV.
Maybe we should just leave it alone. Let the shooter with the best barrel, the best bullets, the best tune, and the best ability win.
Novel concept, huh?