Hello,

509 is a good score and yes you have chances of admission in BC category. 

Following are some colleges in both AU region as well as SVU region in which you can apply for admission.

AU region

1. Guntur Medical College, Guntur.

2. Ranga Raya Medical College.

3. Rajiv Gandhi Institute of Medical Sciences.

SVU region.

4. Sri Venkateswara Institute of Medical Sciences.

5. Kurnool Medical College 

6. Government Medical College, Anantpur.

7. Rajiv Gandhi Institute of Medical Sciences, Kadapa. 

You can apply for admission in MBBS in any of the above colleges in State quota counselling. You have good chances of admission in these colleges as their last year's cut off was around 480 marks. 

Hope this helps.

Good Luck.