I'm shooting the 6DTI as well with the 70grn BK's...DRT.Look at Dtech uppers. I just built a 6mmDTI. 6.8 spc necked down to 6mm. I’m pushing 70 gr BK’s 3350 FPS. Crushes yotes at any distance.
I also built a 243WSSM in a ten twist and it shoots the 65 Hornady Vmaxes and 70 BK's well... both can run on the AR 15