This is my opinion and observations. with regards to the boat loads of 6.5 wizz-bang cartridges being developed and those already out there. I am personally in awe of all these cartridges that are being developed and a myriad of them are basically the same, nothing special; the 6.5 PRC and 6.5 CM are basically worked over 260 Rems. 6.5 Grendel is the unique one but basically a cartridge that is best left to the CQB or target range (slug range too light for any serious hunting). the older cartridges like the 264 Win Mag, the 6.5-06, 6.5X55 Belgium, and 6.5X57 Mauer are serious hunting cartridges and are great and mostly forgotten about due to just being older. now we get to the cartridges that I am just learning about 6.5 SAUM, 6.5-300 Win Mag, 6.5-7MM Weatherby Mag, 6.5-284 Win, 6.5-7MM Rem Mag (wildcat that is standardized as the 264 Winchester...) and others. It seems if the case have been made and can handle a 6.5 slug they have made wildcat cases for the 6.5MM/0.264" projectile. We are always evolving cartridges for specific uses, some target, some combat, some for hunting, even fewer are for the long range stuff. I personally do not see the use of the 6.5 class of cartridges, but people like them for their attributes. I will not deny that. I have watched as the old venerable cartridges have been forgotten for new and pretty/sexy boutique cartridges. Have these new sexy cartridges peaked, specifically the 6.5 CM, and will be set aside for either new sexy ones or for older; more tried and true powerhouses, I can not say. I can speculate that the 264 Win, the 6.5-06, and the best of the European 6.5's will make a comeback. Really only God knows but I pray it will be true. I have one for you, has anyone heard of a 6MM Sako Magnum? I have an example of one in my shop. it is super sexy and would toss a 0.243"/6MM pill pretty fast. I would speculate nearly as fast if not faster than the 243 Weatherby. But again it has been left to the annals of history and dust. I do believe the 6.5 Creedmoore and the 6.5 PRC have peaked and will die off. like every cartridge, there will be diehard advocates of the creed/PRC but I think that there will be another super sexy 6.5 to take it's place. I know a diehard 6.5 fan specifically the 6.5X55 Belgium and the 6.5 Grendel. I personally will be looking back at the older venerable cartridges for inspiration to make a totally unique wildcat in 6.8MM/0.277" bore. I like the look and capacity of the 264 win/7MM Rem case for a heavy slug flinging 270 wildcat. If I ever get the chance to make one, I will. I think it would make a great competitor to the 7MM Rem. Maybe then we will get more development on the 0.277" diameter slugs and get some truly great slugs for the 270 Win, Weatherby, WSM, and the Ackley Improved cartridges in 0.277" diameter.