I have a Vortex Viper 6.5-20x50 AO mildot on my 20 Shilen with 20 MOA Aadmount which does pretty well. I also have a Vortex Diamondback HP 4-16x42 AO in a Warne Skel 20 MOA mount on my Group Buy 18 6.5 Grendel. I think a second focal plane 4-16 scope with an adjustable objective is a good size and weight for a general purpose 6.5 Grendel. Vortex dropped the Diamondback HP series but they still sell the Viper which are also manufactured in the Philippines. Primary Arms scopes, Athalon, SWFA and Swampfox get good reviews. I say see which scopes have the features you like at the price you can afford.
I have a Vortex Viper HST 4-16x44 AO with Target turrets with a VMR-MOA reticle in a 30 MOA Dip mount on my Cz527 6.5 Grendel. The Viper HST can be found on sale for around $500 Dollars. A Friend bought a refurbished Vortex Viper HS 4-16x50 with dead hold reticle. I prefer the VMR MOA or VMR MRAD reticle over the Dead hold and the HS only has 50 MOA of vertical adjustment. I thought the Viper HS made a dandy hunting scope and my friend mounted his Viper HS on a 6.5 Creedmoor bolt action.
Vortex Optics
Vortex Viper HST 4-16x44 AO target turrets VMR-MOA reticle
https://aaoptics.com/VIPER-HS-T-4-16X44-...p_659.html
Viper HS 4-16x44 Dead Hold Reticle
https://aaoptics.com/VIPER-HS-4-16X44-RI..._p_35.html
I have a Vortex Viper HST 4-16x44 AO with Target turrets with a VMR-MOA reticle in a 30 MOA Dip mount on my Cz527 6.5 Grendel. The Viper HST can be found on sale for around $500 Dollars. A Friend bought a refurbished Vortex Viper HS 4-16x50 with dead hold reticle. I prefer the VMR MOA or VMR MRAD reticle over the Dead hold and the HS only has 50 MOA of vertical adjustment. I thought the Viper HS made a dandy hunting scope and my friend mounted his Viper HS on a 6.5 Creedmoor bolt action.
Vortex Optics
Vortex Viper HST 4-16x44 AO target turrets VMR-MOA reticle
https://aaoptics.com/VIPER-HS-T-4-16X44-...p_659.html
Viper HS 4-16x44 Dead Hold Reticle
https://aaoptics.com/VIPER-HS-4-16X44-RI..._p_35.html