Same opinion on the grendel. Good deer caliber but ballistically inferior to many other cartridges out there.
My vote AR-10 in whatever caliber gets your blood to tingle.
Looked at my response and that downigger guy is an a**hole.
Not what i was trying to say. I think gamo is "top of the line" from when my brother was looking. Take a look at the models and see what will fit for your family.
Custom build one for superb accuracy. Im a shilen barrel fan myself. D-tec solutions out of bemidgi mn has done 3 barrels for me. You must be thinking AR-10 if you want deer killing power and range.