There are many factors that lead to the decision of whether you'll get a seat or not like what category you belong to? Etc.

As you said your alll India rank is 381 I'd assume you have scored decent marks and have earned a major possibility of taking a seat in MBBS course.  As you're asking about admission in Karnataka, I think it would be genuine to say you have good chances to get a seat.

Apply for counselling and wait for your call.