NRA Firearm Inspection & Testing Flashcards

What is a proof load and what is its purpose?

Answer: An overpressure test cartridge used to verify structural integrity of a barrel or action

Proof loads are cartridges loaded to a pressure significantly higher than standard maximum to test whether a barrel, action, or complete firearm can safely withstand extreme pressure.

What is the purpose of checking barrel crown concentricity?

Answer: To ensure the muzzle end is uniformly cut perpendicular to the bore for consistent bullet exit

A concentric, perpendicular crown allows propellant gases to release uniformly around the bullet as it exits, maintaining bullet stability and maximizing accuracy.

What does it mean if a firearm exhibits 'trigger creep'?

Answer: The trigger moves rearward a significant distance before the sear releases, instead of a clean break

Trigger creep is the takeup or movement of the trigger prior to the sear release, often felt as a gritty or mushy movement before the shot breaks.

What is a 'lead check' inspection of a revolver cylinder?

Answer: Inspecting the cylinder for lead shaving or buildup at the forcing cone and cylinder throats

A lead check inspection examines the cylinder throat openings and forcing cone for lead shaving, which indicates the cylinder throats or forcing cone are out of dimensional specification.

What condition does a gunsmith check for when examining a semi-automatic pistol's extractor tension?

Answer: Whether the extractor applies sufficient spring tension to grip the cartridge rim for reliable extraction and feeding

Proper extractor tension ensures the extractor snaps over the cartridge rim during feeding and maintains firm contact for reliable extraction after firing.

What is the purpose of a chamber cast in gunsmithing inspection?

Answer: To create a physical impression of the chamber for precise dimensional measurement or to identify damage

A chamber cast uses a low-melting alloy (such as Cerrosafe) poured into the chamber to create a precise replica of its dimensions for measurement or damage assessment.