IIT Kurnool is one of the finest IIITs in India and is highly sought after institute related to design and manufacturing. It is an institute of National Importance and offers 3 of the most in-demand branches of Engineering, with specializations in design except in the branch of Computer Science, in India. Thus it's closing rank is also lower and is getting lower each year due to improving condition of the institute. It is a privately owned institution and thus does not provide any Home Stae advantage as in the case of NITs. You belonging to Kurnool does not help your chances in IIIT Kurnool. Last Year, it closed around 7453 for the branch of Mechanical Engineering which was the highest closing rank among the three branches. Your rank of 403904 is not enough for the seat in IIIT Kurnool, even with the SC quota.

I would strongly advise you to look into some other newer IIITs or GFTIs as now you have to either settle for a lower branch or in some lower college. But still remember, a student can excel irrespective of college he/she is in.

I am attaching last year cutoffs for IIIT Kurnool for your better understanding https://engineering.careers360.com/articles/jee-main-cutoff-for-iiitdm-kurnool