[GeronL]

But Beck also said the “gun act also prohibits someone who is not a dealer from selling a gun to someone who is from out of state.”

??

[ltc8k6]

The undercover agents must have told the sellers that they had a record or that they were from out of state.

You’d have to be a fool to sell to anyone who tells you that, or shows you an out of state ID.

The key word is “knowingly”...

[TheThirdRuffian]

“A person may sell a firearm to an unlicensed resident of his State, if he does not know or have reasonable cause to believe the person is prohibited from receiving or possessing firearms under Federal law. A person may loan or rent a firearm to a resident of any State for temporary use for lawful sporting purposes, if he does not know or have reasonable cause to believe the person is prohibited from receiving or possessing firearms under Federal law. A person may sell or transfer a firearm to a licensee in any State. However, a firearm other than a curio or relic may not be transferred interstate to a licensed collector.”

From the ATF website.

[TheThirdRuffian]

The State of residence is the State in which an individual is present; the individual also must have an intention of making a home in that State. A member of the Armed Forces on active duty is a resident of the State in which his or her permanent duty station is located. If a member of the Armed Forces maintains a home in one State and the member’s permanent duty station is in a nearby State to which he or she commutes each day, then the member has two States of residence and may purchase a firearm in either the State where the duty station is located or the State where the home is maintained. An alien who is legally in the United States is considered to be a resident of a State only if the alien is residing in that State and has resided in that State continuously for a period of at least 90 days prior to the date of sale of the firearm. See also Item 5, “Sales to Aliens in the United States,” in the General Information section of this publication.

[18 U.S.C. 921(b), 922(a) (3), and 922(b)(3), 27 CFR 478.11]

[Cboldt]

the gun act also prohibits someone who is not a dealer from selling a gun to someone who is from out of state

27 CFR 478.29

It's an ATF regulation.