Exactly.
Becoming a viable factory cartridge in the U.S. means approval by the Sporting Arms and Ammunition Manufacturers Institute (SAAMI), made up of manufacturers who want to make sure any factory ammo is safe in any factory firearm chambered for the round. And they have yet to approve a maximum average pressure for any rifle cartridge of over 65,000 PSI.
Another possible hang-up would be consistent chamber dimensions. Different throat lengths wouldn't cut it.
All that aside, SAAMI membership isn't necessary to produce ammunition, and even compliance with their pressure and dimension standards is voluntary among members. A number of small non-SAAMI companies make and sell ammo outside its standards. There's no reason GAP can't make ammo in Hornady cases and sell it. But that wouldn't make the cartridge nearly as available (and popular) as SAAMI-approved factory rifles and Hornady ammunition.
Copper creek is already selling 6.5 Saum ammunition , I reload all my ammo so personally I would just like to see some more brass choices like possibly Lapua,but I would be happy if Remington would start making 7mm Saum brass more available not sure if they are even going to make it anymore, George said he had a couple companies looking to possible make it by this time next year we'll just have to wait and see !
Ga precision is on it's 3rd round of brass and it was suppose to drop down from $1.55 to a $1.10 but I haven't seen it, when the brass becomes a little cheaper I can see it gaining in popularity!