I have given the IPMAT Indore test, but have not applied for Ranchi IIM, is there any chance to apply now?

Yes, 300 out of total 360 marks is a very good score and will put students in the 99 percentile. 

Atharva School of Business considers IPMAT score for admission in Integrated BBA-MBA course. Aspirants can also get admission in Integrated programme based on their scores in MH CET, PERA CET or AU-AIET. Candidates must also meet course-specific eligibility for admission.

IPMAT exam is conducted for two hours or 120 minutes. The sectional time limit is 40 minutes for each section. 

IPMAT, is a gateway for admission to 5 year Integrated Program in Management offered at IIM Indore. IPMAT is a combination of a Bachelor degree and a Masters degree. Students will be given a Bachelor of Arts, Foundations of Management and a Master of Business Administration at the end of the program

IPMAT exam is conducted for two hours or 120 minutes. There are three sections in IPMAT question paper and each section is to be solved within 40 minutes.