Quoted:
I know here in AZ (probably THE most liberal/relaxed state when it comes to gun laws),

Every person within the state who owns or obtains a handgun, in any manner, must present the handgun to either the city chief of police or the county sheriff of the locality where he resides. A certificate of inspection will then be issued containing a description of the handgun inspected and the name, description and thumbprint of the possessor.

Pellet guns are considered firearms in Michigan and thus are regulated by the above provisions. A pellet handgun must be registered and requires a license to purchase. In addition, a license to carry must be obtained to carry concealed or in a vehicle; if it has no serial number, the gun must be taken to the State Police who will stamp a number on the weapon. No person under 18 years of age may possess or use a BB gun beyond the yard of his home unless accompanied by a person over

To purchase a handgun from either a dealer or private individual, the buyer must obtain a license to purchase from the chief of police if the buyer lives in a city, or the county sheriff if he lives in an area without an organized police department. The buyer must be 18 years of age, a U.S. citizen, a resident of Michigan, have no felony conviction, have never been adjudged insane (unless later restored by court order), and score 70% on a basic pistol safety review questionnaire.

.... A person who is eighteen or older, but under 21, may purchase a handgun, but not from a federally licensed dealer who is prohibited from selling a handgun to anyone younger than 21

(x) (1) It shall be unlawful for a person to sell, deliver, or otherwise transfer to a person who the transferor knows or has reasonable cause to believe is a juvenile:

(A) a handgun;or

(B) ammunition that is suitable for use only in a handgun.

(2) It shall be unlawful for any person who is a juvenile to knowingly possess:

(A) a handgun;or

(3) This subsection does not apply to:

(A) a temporary transfer of a handgun or ammunition to a juvenile or to the possession or use of a handgun or ammunition by a juvenile if the handgun and ammunition are possessed and used by the juvenile:

(i) in the course of employment, in the course of ranching or farming related to activities at the residence of the juvenile (or on property used for ranching or farming at which the juvenile, with the permission of the property owner or lessee, is performing activities related to the operation of the farm or ranch), target practice, hunting, or a course of instruction in the safe and lawful use of a handgun;

(ii) with the prior written consent of the juvenile's parent or guardian who is not prohibited by Federal, State, or local law from possessing a firearm, except:

(I) during transportation by the juvenile of an unloaded handgun in a locked container directly from the place of transfer to a place at which an activity described in clause (i) is to take place and transportation by the juvenile of that handgun, unloaded and in a locked container, directly from the place at which such an activity took place to the transferor;or

(II) with respect to ranching or farming activities as described in clause(i), a juvenile may possess and use a handgun or ammunition with the prior written approval of the juvenile's parent or legal guardian and at the direction of an adult who is not prohibited by Federal, State or local law from possessing a firearm;

(iii) the juvenile has the prior written consent in the juvenile's possession at all times when a handgun is in the possession of the juvenile; and

(iv) in accordance with State and local law;

(B) a juvenile who is a member of the Armed Forces of the United States or the National Guard who possesses or is armed with a handgun in the line of duty;

(C) a transfer by inheritance of title (but not possession) of a handgun or ammunition to a juvenile;or

(D) the possession of a handgun or ammunition by a juvenile taken in defense of the juvenile or other persons against an intruder into the residence of the juvenile or a residence in which the juvenile is an invited guest.