Hey,

With 315 marks, you will get a rank between 229715-244438. You can check here https://medicine.careers360.com/articles/neet-result-marks-vs-rank

Based on previous year cut off, you will not get a medical seat under GM category in Karnataka since it closed around a marks of 430-420 in 2019.

Now, cut off varies every depending on a number of factors such as the number of seats available and the number of qualified candidates. To get a list of colleges in which you have a chance of getting MBBS/BDS seat, you can use NEET College Predictor https://medicine.careers360.com/neet-college-predictor?icn=QnA&ici=qna_answer