I need a quiet air rifle. I don't know much about air rifles but from what I've read here and elsewhere it looks like the R7's the best choice. It seems to come with some pretty decent sights. If it's feasible I'd like to leave them on the rifle for indoor shooting but use a scope for longer outside shots.

Is there a mounting system that will allow me to remove the scope for indoor use and reliably return the scope to zero when remounting it? Will I be able to mount a scope low enough to be useable without removing the open sights?

I'll be using this for short range plinking, informal target shooting and maybe head shots on squirrels at 50/60 feet max.
What's a good quality, air rifle compatible scope that won't break the bank? I don't want a big, high magnification scope. It seems a 4x or 6x would be plenty given what appears to be the effective range of the R7.

Thanks.