KAC was one of the first to release the 6.8 SPC IIRC and to my recollection all their advertising showed the PRI mag. I cant say who was first to market with a 6.8 SPC magazine but I believe at that time only C Products of New Britain, Ct and PRI were the only source for 6.8 SPC magazines.
Here is a related article and Remington might have been involved with getting the 6.8 Remington SPC SAAMI approved. Several AR-15 manufacturers sold 6.8 SPC caliber rifles but honestly I was more interested in the 6.5 Grendel and didnt pay as much attention to the 6.8 SPC.
http://demigodllc.com/articles/6.8-mm-sp...s-carbine/
Here is a related article and Remington might have been involved with getting the 6.8 Remington SPC SAAMI approved. Several AR-15 manufacturers sold 6.8 SPC caliber rifles but honestly I was more interested in the 6.5 Grendel and didnt pay as much attention to the 6.8 SPC.
http://demigodllc.com/articles/6.8-mm-sp...s-carbine/