[Quiet]

Your nephew is not considered "immediate family" under CA firearm laws [PC 16720].
Therefore, his grandparent or parent needs to be the person that gifts him the shotgun.

So, your sister (his mom) buys the shotgun and does the 4473/DROS + 10 day wait. After which she can give the shotgun to her son (your nephew), no paperwork required. [PC 27870] If she gives the shotgun to him after 01-01-2014, then he will need to be 18 or older and he will need to register it. [PC 27875]

If you buy the shotgun, then you will have to wait until he turns 18 and transfer it to him through a CA FFL dealer.



Penal Code 16720
As used in this part, "immediate family member" means either of the following relationships:
(a) Parent and child.
(b) Grandparent and grandchild.

Penal Code 27870
Section 27545 does not apply to the transfer of a firearm, other than a handgun, by gift, bequest, intestate succession, or other means from one individual to another, if both of the following requirements are satisfied:
(a) The transfer is infrequent, as defined in Section 16730.
(b) The transfer is between members of the same immediate family.
(c) This section shall remain in effect only until January 1, 2014, and as of that date is repealed, unless a later enacted statute, that is enacted before January 1, 2014, deletes or extends that date.

Penal Code 27875
Section 27545 does not apply to the transfer of a handgun, and commencing January 1, 2014, any firearm, by gift, bequest, intestate succession, or other means from one individual to another, if all of the following requirements are met:
(a) The transfer is infrequent, as defined in Section 16730.
(b) The transfer is between members of the same immediate family.
(c) Within 30 days of taking possession of the firearm, the person to whom it is transferred shall forward by prepaid mail, or deliver in person to the Department of Justice, a report that includes information concerning the individual taking possession of the firearm, how title was obtained and from whom, and a description of the firearm in question. The report forms that individuals complete pursuant to this section shall be provided to them by the Department of Justice.
(d) The person taking title to the firearm shall first obtain a handgun safety certificate, if the firearm is a handgun.
(e) The person receiving the firearm is 18 years of age or older.