Rabbit:
As far as I know, the use of air rifles in the take of turkey has only been legal in California since the year 2000.
The head/neck shot is preferred when using rifles of the power class that I shoot in .20 caliber. A high quality .20 caliber springer like an R-1 or R-9 is accurate enough to hit that KZ out to 50 yards. If I keep my skills up, so am I.
I practice on a life-size head /neck target that I photocopy from the back of the CA DFG Turkey Hunting Guidebook.
It is not something I would recommend that more "causual" hunters unwilling to put the time in even try. But with practice, virtually anyone could develop the shooting skill required to pull it off.
If I was willing to shoot a more powerful rifle in a larger caliber -like a .25 caliber Beeman Kodiak for example, or a larger bore PCP, then I wouldn't be nearly as wedded to head and neck shots on turkey as I am.
With the head / neck shot, though, even a "gutless" little R-9 in .20 is enough gun.
As for it being "quite an accomplishment," it really isn't if you train for it. All it takes is practice.
-JP