Wouldn’t zero on a 6.5 grendel - Athlon Optics Talos BTR 4-14 x 44 mm Rifle Scope 30mm First Focal Plane

I built a 6.5 grendel for hunting and just daily shooting. I was looking for a mid level FFP scope and thought I would give this athlon a try. After two different mounts I finally found one that I was satisfied with. I was happy with the look and eye feel. After a bore sight I went out to my 50 yard range. I was all over the paper with the first 50 rounds. I upgraded to some hornady ammo to see if this would help. While it did tighten my group up I still couldn’t hit inside a softball consistently. I did some reading and thought maybe it was my barrel needing broken in. I went ahead and checked all my torque spec and made sure my scope was tight. After another 50 rounds I still couldn’t get it to group. I was torn is it the gun or the scope. The easiest thing to do was slap a scope on from another gun. I put on a vortex diamondback and was quickly shoot walnut size groups with the hornady ammo. I’m not sure if I can return this product or not.