This may sound counter-intuitive, but you could try a heavier buffer.
If the carrier moves too early, expansion in the gas chamber behind the bolt is rapid, then it vents after a certain amount of travel.
If you allow more gas pressure to build in there over a longer period of time, you might be able to initiate a more energetic carrier inertia.
Aside from opening the port, spring weight and carrier weight are your options.
You'll probably end up opening the port and dialing in for the Hornady load.
If the carrier moves too early, expansion in the gas chamber behind the bolt is rapid, then it vents after a certain amount of travel.
If you allow more gas pressure to build in there over a longer period of time, you might be able to initiate a more energetic carrier inertia.
Aside from opening the port, spring weight and carrier weight are your options.
You'll probably end up opening the port and dialing in for the Hornady load.
NRA Basic, Pistol, Rifle, Shotgun, RSO
CCW, CQM, DM, Long Range Rifle Instructor
6.5 Grendel Reloading Handbooks & chamber brushes can be found here:
www.AR15buildbox.com
CCW, CQM, DM, Long Range Rifle Instructor
6.5 Grendel Reloading Handbooks & chamber brushes can be found here:
www.AR15buildbox.com