.25 good springer ?

A break barrel .25 is about as easy to load as it gets. The one I am linking here is a fine rifle that will shoot well, is not too hard to cock, and is accurate enough to pass the ten dimes challenge... Price isn't bad.

Really, really do like this rifle:

https://www.airgunnation.com/topic/bsa-lightning-grt-25-hn-ftt-twenty-nine-yards/

If you meant that $600 was you high end WITH scope. It might be a good choice. You would have enough left over from the rifle to put a good piece of glass on it. If you are willing to spend $600 on the rifle and whatever on glass then the HW line is a good place to look.