I would say it depends greatly on which PCP and which centerfire you are comparing. Cheap PCP vs. great PB is going to be like 8 to 1, or even 10 to 1. A great PCP vs. a a not-so-great PB is probably going to approach a 4 to 1 ratio.
We are just talking about the maximum reasonable useful range of air rifles ,rim fires and center fire rifles. You would have to reasonably assume we are talking ideal conditions and the best of the best rifles and ammo and top notch shooters. We are comparing apples to apples or what’s the point.
Most of us have watched Bob’s video’s (and others ) he’s hitting pest birds at 100 yards with his FX equipment . Do you think he would be able to hit a 10 inch gong with a 308 at 600 yards if we gave him equipment of equal quality or a say a 3 inch target at 150 yards with an Anschutz 22 and eley ten X ammo . I’m pretty certain it’s a sure thing.
If the conditions or equipment isn’t of similar quality or the shooter(s) of the same ability of course you can’t expect similar results.
We all know the biggest variable is the person pulling the trigger
The point being made is the air rifle is holding its own and I would say possibly surpassing the others with in it’s range Maybe it always has but the RANGE is getting longer.
I’m not that great of a shot but I’m hitting sparrows pretty consistently at 45 yards with my air rifles. I don’t think that would have been remotely possible for me what 5 years ago??? Maybe I’ll improve and reach out even further.
I drive myself nuts shooting pest birds. I’ll smack a sparrow and 15 minutes later a pigeon will light in the same spot and I’ll miss him. That’s clearly proof of shooting skills or in my case the lack there of . I’ve done that pretty often. Hit groundhogs at over 300 and miss a close one.
I have learned that with air rifles ten yards can amount to a big difference in your point of aim. You need to know the exact distance and elevation as well. BUT if you hit them all what’s the point