Depending on jurisdiction the process/ requirements may vary a bit. In Delhi the following process is followed.
Documents required: -
-Application on plain paper mentioning the reasons for addition.
-Copy of arms license booklet depicting clearly the no. and type of weapons already held by the licensee.
-Prescribed affidavit
-Documents pertaining to reasons of addition.
In case of death/transfer of weapon on inheritance basis:-
-Death certificate of the licensee in case of death only.
-Weapon deposit permission in case of death of the licensee.
-Weapon deposit receipt issued by the authorized arms dealer or the police station as the case may be.
-Indemnity bond
-NOC given by other legal heirs that they have no objection, if weapon is transferred to the applicant.
-Arms license of the deceased or the transferor as the case may be.
-In case of transfer of weapon the NOC/consent of licensee who intends to transfer his weapon to his legal heir.
-Affidavit from the licensee to the effect that he/she has not objection for the transfer of the arm in the name of applicant and he/she shall not apply in future.
In case of renowned shooters / sports activities.
-Participation certificate of at least one State Level/Zonal Level/National Level Shooting Competition recognized by National Rifle Association.
-Certificate / recommendation from NRAI duly attested by Ministry of Youth Affairs and Sports, Govt. of India, New Delhi, for addition of a weapon for practice and participation in the Shooting Competition.
In case of retainers due to family safety / protection of crops.
-Consent from the main licensee as well as the retainer.
-Proof of agricultural activities, if applicable.
-Proof of threat to the family, if applicable.
-All the documents are same as required for fresh grant of license.
Procedure: -
Application can be made along with the required documents on any working day in the Licensing Unit during public dealing hours between 9.30 AM to 12.30 PM or by post. Approval or rejection will be conveyed to you by post. In case of approval, you may come for depositing the requisite fee and to get the requisite endorsement on the Arm License on any working day during public dealing hours. The sample forms can be down loaded form the hyper links provided above or else can be obtained from the licensing Unit.
Information from
http://delhipolicelicensing.gov.in/Home/arms#section5