NRA NRA Firearm Inspection & Testing 2 — Questions and Answers
Question 1: What is a proof load and what is its purpose?
- A standard factory load used during accuracy testing
- An overpressure test cartridge used to verify structural integrity of a barrel or action (Correct answer)
- A reduced-power load for testing function
- A gauge round used for headspace testing
Correct 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.
Question 2: What is the purpose of checking barrel crown concentricity?
- To verify the barrel is the correct length
- To ensure the muzzle end is uniformly cut perpendicular to the bore for consistent bullet exit (Correct answer)
- To measure the thickness of the barrel walls
- To check the thread pitch at the muzzle
Correct 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.
Question 3: What does it mean if a firearm exhibits 'trigger creep'?
- The trigger requires too much force to pull
- The trigger moves rearward a significant distance before the sear releases, instead of a clean break (Correct answer)
- The trigger resets very slowly after firing
- The trigger physically moves sideways during firing
Correct 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.
Question 4: What is a 'lead check' inspection of a revolver cylinder?
- Checking for cracks in the cylinder using lead dye
- Measuring the cylinder gap
- Inspecting the cylinder for lead shaving or buildup at the forcing cone and cylinder throats (Correct answer)
- Verifying the cylinder rotates the correct direction
Correct 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.
Question 5: What condition does a gunsmith check for when examining a semi-automatic pistol's extractor tension?
- Whether the extractor is made of steel or polymer
- Whether the extractor applies sufficient spring tension to grip the cartridge rim for reliable extraction and feeding (Correct answer)
- Whether the extractor groove in the slide is properly machined
- Whether the extractor spring is the correct length
Correct 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.
Question 6: What is the purpose of a chamber cast in gunsmithing inspection?
- To protect the chamber from rust during storage
- To create a physical impression of the chamber for precise dimensional measurement or to identify damage (Correct answer)
- To resize a chamber to correct dimensions
- To mark the chamber for identification purposes
Correct 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.
NRA NRA Firearm Inspection & Testing 2
What is a proof load and what is its purpose?