This is was done after consulting every AR forum and polling the information from different discussions by several thousand experts on the field. We not aware that the Special Forces/SWAT/SEAL/RECON/PMC community comprised some 300 thousand active members.
Hat Tip to PMH
The chart implies that anyone makes reliable piston operated .300 blk AR15s.
Even LWRC started making DI guns due to the difficulties inherent to making .300 BLK guns run reliably.
No FAL option, so OBVIOUSLY I operate! 😉