NRA NRA Tools & Equipment for Gunsmithing 2 — Questions and Answers
Question 1: What is a 'reamer' and what is it used for in gunsmithing?
- A cleaning brush with a spiral design
- A precision rotary cutting tool used to cut or finish a chamber to exact dimensions (Correct answer)
- A tool for smoothing feed ramps
- A drill bit for creating gas ports in barrels
Correct answer: A precision rotary cutting tool used to cut or finish a chamber to exact dimensions
A chamber reamer is a precision cutting tool designed to cut a chamber to exact SAAMI or custom specifications in a barrel blank.
Question 2: What is a 'lathe' primarily used for in a gunsmithing shop?
- Cutting checkering patterns on stocks
- Turning, threading, and facing metal parts to precise dimensions for barrel work, custom parts, and fitting (Correct answer)
- Applying chemical finishes to metal parts
- Bending sheet metal for magazine construction
Correct answer: Turning, threading, and facing metal parts to precise dimensions for barrel work, custom parts, and fitting
A metal lathe is essential for barrel threading, tenon turning, crown cutting, and fitting custom parts to precise tolerances.
Question 3: What is the purpose of a 'Dremel tool' or die grinder in gunsmithing, and what caution applies?
- Primary tool for all metal removal — no special caution needed
- Used for light deburring, polishing, and fitting work — caution: removing too much metal can render parts unsafe or non-functional (Correct answer)
- Used only for cutting wood stocks — no caution needed for metal
- A primary chambering tool — no lathe required
Correct answer: Used for light deburring, polishing, and fitting work — caution: removing too much metal can render parts unsafe or non-functional
Rotary tools are useful for light fitting and polishing but must be used carefully, as excessive material removal can weaken or destroy critical components.
Question 4: What is a 'pin punch set' used for in firearm disassembly and assembly?
- Driving out drift pins, roll pins, and cross pins that retain components in the action (Correct answer)
- Checking chamber concentricity
- Installing scope rings without marring the finish
- Removing stuck cases from chambers
Correct answer: Driving out drift pins, roll pins, and cross pins that retain components in the action
Pin punches are used to drive out the various pins that hold firearm components (trigger groups, barrel keys, sights) in place during disassembly.
Question 5: What is an 'ultrasonic cleaner' used for in a gunsmithing shop?
- Stripping old bluing from metal parts using ultrasound
- Using high-frequency sound waves in a cleaning solution to remove carbon, oil, and debris from small parts without disassembly of each part (Correct answer)
- Inspecting bore condition using sonic waves
- Hardening metal through ultrasonic vibration
Correct answer: Using high-frequency sound waves in a cleaning solution to remove carbon, oil, and debris from small parts without disassembly of each part
Ultrasonic cleaners use cavitation bubbles created by ultrasound to agitate cleaning solution, loosening and removing fouling from complex parts efficiently.
Question 6: What does a 'muzzle crown cutter' do and why is a proper crown important?
- It cuts checkering at the muzzle for appearance only
- It cuts a precise, uniform crown (muzzle face geometry) that ensures uniform gas release as the bullet exits, preserving accuracy (Correct answer)
- It removes the barrel's muzzle threads after suppressor use
- It polishes the bore at the muzzle to reduce leading
Correct answer: It cuts a precise, uniform crown (muzzle face geometry) that ensures uniform gas release as the bullet exits, preserving accuracy
A proper crown ensures gas exits uniformly around the bullet, and any damage or irregularity in the crown can cause erratic bullet flight and poor accuracy.
NRA NRA Tools & Equipment for Gunsmithing 2
What is a 'reamer' and what is it used for in gunsmithing?