Disclaimer: This is my opinion and is somewhat old school and this is almost a rant!. I frequently get asked what kind of scope to put on a big bore hunting airgun? I prefer smaller, lightweight, lower power scopes. One of my favorites is a Nikon Monarch 1.5-4.5X scope. Smaller scopes usually have smaller objectives and can be mounted lower for proper cheek weld. You knew the cheek was a critical contact point that greatly increases hold stability right? It also allows for proper eye alignment eliminating the need for adjustable objectives to compensate for parallax error. It is hard to aim precise and hold steady if your head is up off the stock wobbling around. You have seen the adjustable cheek rests on all the high end competition guns right? They are there for a reason. Lower mounting equates to a better balanced gun more likely to recoil consistently. Remember your scope is an aiming tool, not a spotting scope or binoculars. A deer at 40 yds will appear as if at 10 yds with a simple 4X scope. 4X will give enough magnification to head shoot squirrels at 50yds too. Without that weight adding AO on a high magnification variable you are much less likely to have game suddenly appear at close range and be caught with a scope set so you cannot see your quarry, or need to make game alerting movement to adjust your scope (you have already had that happen haven't you?). Not to mention the pleasure of a day afield with a light weight hunting rig. I find many light weight low cost fixed power scopes designed for firearms will work well on pcp airguns with their parallax readjusted down to 40 yds. If you search the net you will find descriptions on how to do this simple 10 minute modification to make long range parallax firearm scopes useful for typical airgun ranges.
Note how the loading port is not covered by the smaller scopes (top and bottom guns). The middle Sam Yang was sold this way as a "Combo Package".