Hi

You have not mentioned the category you belong to so I am  assuming  you from general category

It's quite difficult to predict that whether you will get seat or not as cut off marks for medical colleges keeps changing every year depending upon various factors like number of students that appeared in the exam, kind of marks obtained by them , toughness level of the examination etc.

But when we go through previous data then it suggests that with 300 marks you may not get into a Government Medical College, But yes you can go for private medical college and deemed universities
To get the list of colleges in which you have chances, you can go through our college predictor at

https://medicine.careers360.com/neet-college-predictor?icn=QnA&ici=qna_answer

It gives you a personalized report with top college in which you have chances for admission , with the help of predicted colleges you can make better choice while filling your choices of colleges during your counselling

Thankyou