Childproof Handgun Act of 2005 - Amends the Federal criminal code to prohibit any person who is not a licensed collector from manufacturing, selling, delivering, or transferring a handgun that cannot be personalized, with exceptions for individuals acting under the authority of the United States, a State, or a political subdivision. Defines "personalized" to mean a handgun that incorporates a device or feature that: (1) allows the handgun to be fired only by a particular individual; (2) is not capable of being readily deactivated; and (3) may allow the handgun to be personalized to one or more additional individuals.

Directs the Comptroller General of the United States to conduct a study to determine whether the technology involved in personalizing firearms will be commercially feasible within five years considering criteria including the reliability of the technology and the difference in price for personalized firearms and equivalent firearms that are not personalized.