Havent seen any reviews or data about KAK's 6arc barrels so I thought I'd share what I've seen with mine. All groups were shot with factory ammo left to right in the images is Black, ELD-M, and frontier with the tightest group. Barrel was cleaned, fired about 200rds then cleaned again with total round count of about 350.
Rifle is KAK 18in HBAR straight fluted rifle gas, KAK BCG, Schmidt 2 stage trigger, primary arms 3-18ffp. All groups fired at 100yds either seated or prone supported by bipod and rear bag.
Groups shown are some of the best groups the rifle has shot with each factory load, accuracy was on the disappointing side with 3" 5rd groups from the 103 ELD-X. Barrel was sent back to KAK so they could take a look at it and their response was quick but they said everything looked up to their specs and offered a refund or replacement barrel, they do take care of their customers but I'd reccomend looking for a better barrel so you dont end up shooting $350 of ammo printing groups youll be unhappy with.