looks like somebody fed and watered 6mm PPC until it grew.

The SAAMI datasheet with dimensions of the 6.8 Western, pressure and "SAAMI typical" bullet mass/velocity can be found on saami.org  among the list of new cartridges. The specifications are from November 2020.

Its basically a 6.8 x 51 with a 14 mm case diameter.

MAP: 65,000 PSI

175 gr / 2840 fps (24" barrel)

https://saami.org/wp-content/uploads/2020/11/6.8-Western-Public-Introduction-Orig-2020-11-01.pdf

You can only hope with more skill than .300BLK or 6.5 Creedmoor  .

I am always surprised at amateurish underdeveloped calibers that make it to mass adoption. 300BLK is an absolute disaster when it comes to making it shot accurately, 6.5Creedmoor is probably the most inaccurate of any 6.5calibers ,way worse than either .223rem or  .308win, there is just something inherently wrong with both calibers internal ballistics. While Creedmoor can be made to shot but is never on the level of competition .300BLK is a nightmare to get sub 1moa even out of the best guns and barrels. Absolute abomination,  7.63x39 is a fucking benchrest marvel in comparison, budget  ammo with simple FMJ bullets groups like  .300BLK with best match components.

Perhaps the main reason is .300BLK lineage, 30Whisper when developed was benchmarked against 9x19 out of MP5SD  6-9inches at 100y so 2-3moa seemed like a success. Less understanding is for the 6.5Creedmoor that took much from David Tubb's family of cartridges and just made something that was worse in every aspect.