I checked forum member mel 28 6.5 Grendel and he used a +2 gas system. His rifle barely had enough gas to cycle without the suppressor. Here is a link to a thread where mel did load development for his 28 6.5 Grendel. It mentions his 28 build had a +2 gas system.
https://www.65grendel.com/forum/showthre...nch-barrel
Here is a link to a google custom search feature. You can search for threads where someone might have built a 26 6.5 Grendel. I know Bwaites has a 28 6.5 Grendel but I dont remember anyone building a 26 6.5 Grendel.
https://cse.google.com/cse?cx=0163689474...cu1o&hl=en
https://www.65grendel.com/forum/showthre...nch-barrel
Here is a link to a google custom search feature. You can search for threads where someone might have built a 26 6.5 Grendel. I know Bwaites has a 28 6.5 Grendel but I dont remember anyone building a 26 6.5 Grendel.
https://cse.google.com/cse?cx=0163689474...cu1o&hl=en