NRA NRA Tool Usage & Shop Equipment 1 — Questions and Answers
Question 1: What is the purpose of a barrel vise in gunsmithing?
- To hold the barrel while polishing the bore
- To securely hold the barrel while torquing or removing the action from the barrel (Correct answer)
- To measure barrel dimensions
- To align the barrel with the receiver during assembly
Correct answer: To securely hold the barrel while torquing or removing the action from the barrel
A barrel vise clamps around the barrel using non-marring inserts to hold it securely while applying torque to install or remove the action or muzzle devices.
Question 2: What is a headspace gauge set used for in gunsmithing?
- To measure the depth of rifling
- To verify that a chamber's headspace dimension is within safe specifications using GO, NO-GO, and FIELD gauges (Correct answer)
- To check the depth of the barrel crown
- To measure trigger pull weight
Correct answer: To verify that a chamber's headspace dimension is within safe specifications using GO, NO-GO, and FIELD gauges
Headspace gauge sets use GO, NO-GO, and FIELD gauges to confirm that the chamber headspace is within SAAMI-specified tolerances for safe operation.
Question 3: What is an action wrench used for?
- To tighten scope ring screws
- To provide torque on the receiver when removing or installing barrels (Correct answer)
- To adjust trigger pull weight
- To remove firing pins from bolts
Correct answer: To provide torque on the receiver when removing or installing barrels
An action wrench fits the receiver and provides a controlled point to apply torque when threading barrels on or off, preventing damage to the action.
Question 4: What is the purpose of a trigger pull gauge?
- To measure the length of the trigger shoe
- To measure the force required to fire the firearm by pulling the trigger to the break point (Correct answer)
- To set the overtravel of a trigger
- To measure spring tension in the trigger group
Correct answer: To measure the force required to fire the firearm by pulling the trigger to the break point
A trigger pull gauge measures the amount of force, typically in ounces or pounds, required to pull the trigger to the point where the firearm fires.
Question 5: What is the primary use of an ultrasonic cleaner in a gunsmith shop?
- To polish metal surfaces to a mirror finish
- To clean small parts and assemblies using high-frequency vibration in a solvent bath (Correct answer)
- To remove bluing from metal parts before rebluing
- To test spring tension
Correct answer: To clean small parts and assemblies using high-frequency vibration in a solvent bath
Ultrasonic cleaners use high-frequency sound waves to agitate a solvent bath, loosening and removing carbon, grease, and fouling from complex parts and small assemblies.
Question 6: What is a receiver action block used for?
- To hold the receiver securely in a vise without marring the receiver finish (Correct answer)
- To block the action during transport
- To prevent the trigger from being pulled during disassembly
- To support the receiver during stock fitting
Correct answer: To hold the receiver securely in a vise without marring the receiver finish
An action block clamps into the receiver and provides a solid grip point for the vise to hold the action securely without damaging the receiver's exterior finish.
NRA NRA Tool Usage & Shop Equipment 1
What is the purpose of a barrel vise in gunsmithing?