Hello  in AP cutoff marks is usually around 498 in private medical colleges and around 530 in government. However you may easily get a government BDS college with your marks.  Visit this site for more info https://medicine.careers360.com/articles/neet-cutoff-ap 

Also you can try our college predictor app https://medicine.careers360.com/neet-college-predictor?utm_source=google-search&utm_medium=paid&utm_campaign=neet-clgpd . As far as St Johns Meical College is concerned,The cutoff marks depend on many factors like the number of students who took the exam, level of the exam and number of seats available among others. Therefore, it isn’t correct to speculate the cutoff marks. However, I can provide you with the last year data which will give you some idea of the cut off marks required.

Firstly, the seat reservation policy of St John's Medical College, Bangalore does not include OBC category, you can check the seat reservation and cut off rank in the table given below-

All the best.