You don’t. There is no registration in AZ, there is no option to register, there is no registry, and there is no way to register a firearm in AZ. Period.
In Fact, according to ARS 13-3108, its illegal for the state or any political subdivision of the state to register firearms
“But what about the paperwork you fill out when you buy one at a gun store?”
That form is called a 4473. It’s essentially a background check authorization form. Yes, the firearms information and yours is recorded on the form, however, all 4473’s are kept by the FFL who performed the transfer for a period of 20 years. If the FFL expires before that time, then and only then will they send the 4473’s to the ATF. The only purpose for this it to track the firearm, from the manufacturer, through the line of distribution, to the first sale. This is only done in the event that the firearm was recovered at a crime scene and an ATF Trace is requested. Otherwise, the form will never leave the filing cabinet in the FFL’s shop. Nobody but the FFL has that information and they cannot share it unless a trace request is made by the ATF. [27 CFR 478.129(b)]
“Ok, so what about that phone call? Aren’t they calling the Fed’s?”
That’s an NICS Background check. It’s a call to the FBI National Instant Criminal Background Check System. The FFL gives them your identifying information, and they are either told “Proceed”, “Denied”, Or “Delayed”. Information regarding the firearm being transferred is not given, nor recorded. That’s it. Furthermore, according to FOPA (Firearm Owners Protection Act of ’86) it’s illegal for them to record such information.
[18 U.S.C. 926]
“What about the ATF Form 3310.4 Report of Multiple Sale of Pistols or Revolvers?”
This form is filled out in addition to a 4473 when two or more handguns are sold to the same individual in a five-business day period. Three copies are made. The first is sent to the ATF’s Tracing Center and filed away. This can be searched for using the serial number of the firearms to fast-track the trace process. The ATF believes that if an individual purchases more than one handgun in such a quick time that they may be conducting straw purchases. Hence the reporting to fight illegal straw purchases. The second is sent to the state or local police force, I’m sure that the Sheriff’s Office simply puts it in a box and sets them in a dark room somewhere. Then the third copy is kept by the FFL with the 4473. They are only required to be kept for 5 years. [27 CFR 478.126a and 478.129]
*Note: Obviously this exempts National Firearms Act (NFA) Firearms like Machine Guns, Short Barreled Rifles, Short Barreled Shotguns, and Silencers. NFA firearms must be registered and tax stamps paid when transferred between individuals and trusts. (26 U.S.C. § 5841)
**This is provided as a Legal Information Resource and should not be treated as legal advice.