Rules say: Apply to collector of your district. Establish reasonable reason for holding a firearm. Seek police clearance. License is issued in 3-6 months.
Reality: Would be easier to get it through an existing arms license holder who has experience in dealing with the procedure or through brokers (usually arms sellers) etc. But last I had checked, no small firearm (revolver/pistol) licenses were being issued in Mumbai. Only 12 gauge rifles and above license were being issued if there was a reasonable reason for holding the firearm. It could be a Mumbai only thing though. So you need to check with your local collector office if they allow small firearms or not.
Other possible ways for you: Hire a security guard who has arms license. Usually they also have licenses for rifles/shotguns only. So you don't need a license at all. Another way is if you inherit a firearm (in a will for example) from some family member. Then you can apply for a license and get it provided you have a clean record.
