Hi Sandeep.Handa,
Are you using SQL Server Reporting Services(SSRS) SharePoint integrated mode? If so, you can assign the around 50 users the permissions to access the library, which is used for storing the report, then the users can be able to access the reports.
Please make sure the users have the permissions to access the external data source if the reports are using Windows Integrated authentication.
Additionally, in order to get better assistment, I would suggest you reposting the question in SSRS forum:
http://social.technet.microsoft.com/Forums/en/sqlreportingservices/threads
Thanks,
Jinchun Chen
Jinchun Chen
Forum Support
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