Congratulations for your result. This is the first time JIPMER will be giving admission on the basis of Neet Score. So we don't have any idea about the previous year's cutoffs, we don't have any reference. But there are total 249 seats (JIPMER Puducherry (187) and Karaikal campus (62)) offered for MBBS in JIPMER. Among these 249 seats, 55 seats are reserved for General candidates in Puducherry campus and 19 seats for general candidates in Karaikal campus. So it can be expected that an all India rank within 100 to 150 you can get you a seat in JIPMER Puducherry. Now as you told, you have secured 305 rank (however category not mentioned) in Neet 2020 out of 720, it might be difficult to get Puducherry campus but you have fair chances of getting Karaikal. Also you can use our Neet college Predictor tool to know about your admission possibilities through Neet based on your score and rank
http://medicine.careers360.com/neet-college-predictor?icn=QnA&ici=qna_answer