Yes- air weapons are amongst the few firearms it remains legal for a private individual to own in the UK.
You need to tell us which rifle. Chances are that there is some legal way to own it.
Depends on where you are.
Do you mean an air Rifle? NO, Not in the United States.
no.
Yes
yes
no if he has a permit
Depends on the laws where you live.
Laws on this vary by country.
Yes. An air rifle is not considered a firearm, thus a felons possession is not limited.
Federal law says 18.