Except as provided in paragraph (b), any ATF officer, when there is reasonable cause to believe a violation of the Act has occurred and that evidence of the violation may be found on the premises of any licensed manufacturer, licensed importer, licensed dealer, or licensed collector, may, upon demonstrating such cause before a Federal magistrate and obtaining from the magistrate a warrant authorizing entry, enter during business hours (or, in the case of a licensed collector, the hours of operation) the premises, including places of storage, of any such licensee for the purpose of inspecting or examining:

Any records or documents required to be kept by such licensee under this part and

Any inventory of firearms or ammunition kept or stored by any licensed manufacturer, licensed importer, or licensed dealer at such premises or any firearms curios or relics or ammunition kept or stored by any licensed collector at such premises.

Any ATF officer, without having reasonable cause to believe a violation of the Act has occurred or that evidence of the violation may be found and without demonstrating such cause before a Federal magistrate or obtaining from the magistrate a warrant authorizing entry, may enter during business hours the premises, including places of storage, of any licensed manufacturer, licensed importer, or licensed dealer for the purpose of inspecting or examining the records, documents, ammunition and firearms referred to in paragraph (a) of this section:

In the course of a reasonable inquiry during the course of a criminal investigation of a person or persons other than the licensee,

For insuring compliance with the recordkeeping requirements of this part:

Not more than once during any 12-month period, or

At any time with respect to records relating to a firearm involved in a criminal investigation that is traced to the licensee, or

When such inspection or examination may be required for determining the disposition of one or more particular firearms in the course of a bona fide criminal investigation.

Any ATF officer, without having reasonable cause to believe a violation of the Act has occurred or that evidence of the violation may be found and without demonstrating such cause before a Federal magistrate or obtaining from the magistrate a warrant authorizing entry, may enter during hours of operation the premises, including places of storage, of any licensed collector for the purpose of inspecting or examining the records, documents, firearms, and ammunition referred to in paragraph (a) of this section (1) for ensuring compliance with the recordkeeping requirements of this part not more than once during any 12-month period or (2) when such inspection or examination may be required for determining the disposition of one or more particular firearms in the course of a bona fide criminal investigation. At the election of the licensed collector, the annual inspection permitted by this paragraph shall be performed at the ATF office responsible for conducting such inspection in closest proximity to the collectors premises.

The inspections and examinations provided by this section do not authorize an ATF officer to seize any records or documents other than those records or documents constituting material evidence of a violation of law. If an ATF officer seizes such records or documents, copies shall be provided the licensee within a reasonable time.