To provide an incentive for firearm owners to sell their firearms safely and responsibly.

Keeping Guns From Criminals Act This bill amends the federal criminal code to modify the criminal liability standard for certain firearm sales or transfers. Current law makes it a crime for any person to knowingly sell or transfer a firearm to a prohibited person (i.e., a person who is prohibited from possessing or receiving a firearm). This legislation eliminates the "knowingly" standard to impose criminal liability on any person who sells or transfers a firearm to a prohibited person, regardless of whether such seller or transferor knows that the buyer is a prohibited person. A defendant seller or transferor may assert as an affirmative defense against prosecution evidence to prove that the buyer or recipient passed a background check or possessed a valid concealed carry permit in the state of transfer. The affirmative defense does not apply if defendant knew or had reasonable cause to believe the buyer or recipient was a prohibited person.