Romero-Martinez first argues that the serial numbers on the slide and barrel do not qualify for the enhancement because they do not fall within the federal definition of a "firearm." Romero-Martinez contends that the slide and barrel are not part of the firearm because they may be detached from the gun and are not part of the "frame or receiver" of the weapon.
The applicable definition of a "fire-arm" is set forth by 18 U.S.C. § 921(a)(3), which provides in part:
(A) any weapon (including a starter gun) which will or is designed to or may readily be converted to expel a projectile by the action of an explosive;
(B) the frame or receiver of any such weapon;
(C) any firearm muffler or firearm silencer; or
(D) any destructive device. Such term does not include an antique firearm.
The definition is set forth in the disjunctive and therefore any device meeting any of the definitions qualifies as a firearm (if it is not an antique). "Destructive device" is further defined in 18 U.S.C. § 921(a)(4) and does not apply to the gun Romero-Martinez possessed. While it is true that the slide and barrel would not fall within definition (B) as they are not part of the "frame or receiver," it is clear that the slide and barrel fall within definition (A). Both parts are necessary to operate the weapon, and without them the gun cannot "expel a projectile by the action of an explosive." As such, it would be counterintuitive to exclude these components from the definition of firearm when they are necessary to complete the very action that makes a gun a "firearm" under part (A). Thus, at least when assembled as a functional weapon, the slide and barrel are part of a "firearm" under federal law.
Under Romero-Martinez's interpretation, the only objects meeting the federal definition of "firearm" would be 1190*1190 those incapable of firing a projectile by themselves. Congress did not intend such a limitation. We hold that, under 18 U.S.C. § 921(a)(3), both fully assembled guns, as well as major components of guns (i.e. the frame or receiver), qualify as "fire-arms." As such, altering or obliterating serial numbers on these components, at least when assembled as a functional weapon, qualifies for an enhancement under section 2K2.1(b)(4).
B.
Romero-Martinez next argues that the serial numbers on the slide and barrel do not qualify for the enhancement because they are not required by federal law. This argument is foreclosed by Carter.
Carter held that a serial number was "altered or obliterated" when "accurate information [is made] less accessible." 421 F.3d at 910. Carter thus focuses on whether the information was accurate, not whether it was required by federal law. There is no argument in this case that the serial numbers on the slide and barrel were not accurate information.