Hi aspirant,

The cutoff marks change every year. It's depends upon number of students that appeared in examination, number of seats available in colleges, difficulties of question paper, reservation catagory, previous years cutoff trends, etc.  According to previous years cutoff, candidates who belong to SC catagory required at least 300 to 350 marks for getting government bds college in karnataka.

You can use neet college predictor to know which college you may get with your marks. That is mentioned below:-
https://medicine.careers360.com/neet-college-predictor?icn=QnA&ici=qna_answer
Hope this helpful. Best of luck.