With most scopes your going to run out of elevation adjustment around 800 yards if you shoot close to sea level. At higher elevations in the mountains out west you might get by without a 20 MOA mount. The higher magnification scopes come at the penalty of more bulk and weight on your rifle.
I have a 20” 6.5 Grendel and I put a Vortex Viper 6.5-20x50 mil dot scope in a 30 mm one piece 20 MOA mount. A Friend put a Vortex PST 4-16x50 on his 18” 6.5 Grendel with mil reticle. I like both scopes and another Friend put a Mark AR Leupold 4-12 on his 18” 6.5 Grendel. I think any scope in these magnification range are a good fit for the 6.5 Grendel.
My last 16” 6.5 Grendel I assembled I used a Warne 1” tube 20 MOA mount.
I have a 20” 6.5 Grendel and I put a Vortex Viper 6.5-20x50 mil dot scope in a 30 mm one piece 20 MOA mount. A Friend put a Vortex PST 4-16x50 on his 18” 6.5 Grendel with mil reticle. I like both scopes and another Friend put a Mark AR Leupold 4-12 on his 18” 6.5 Grendel. I think any scope in these magnification range are a good fit for the 6.5 Grendel.
My last 16” 6.5 Grendel I assembled I used a Warne 1” tube 20 MOA mount.