NRA NRA Firearm Mechanics & Operation 2 — Questions and Answers
Question 1: What is the primary function of the recoil spring in a semi-automatic pistol?
- To return the slide forward and absorb recoil energy (Correct answer)
- To cock the hammer
- To eject the spent case
- To feed ammunition from the magazine
Correct answer: To return the slide forward and absorb recoil energy
The recoil spring absorbs the energy of the slide moving rearward and then drives the slide back into battery.
Question 2: What is the term for the condition when a firearm's bolt or slide is fully forward and locked into battery?
- Cocked and locked
- In battery (Correct answer)
- Cycled
- Indexed
Correct answer: In battery
A firearm is said to be 'in battery' when the bolt or slide is fully forward and the action is locked, ready to fire.
Question 3: What determines the lock time of a firearm?
- The weight of the trigger pull
- The time from trigger release to primer ignition (Correct answer)
- The length of the barrel
- The rate of the recoil spring
Correct answer: The time from trigger release to primer ignition
Lock time is the elapsed time between trigger release and primer ignition, influenced by firing pin weight and spring tension.
Question 4: What is the function of the gas port in a gas-operated semi-automatic rifle?
- To vent excess pressure safely
- To bleed propellant gas to cycle the action (Correct answer)
- To cool the barrel
- To regulate chamber pressure
Correct answer: To bleed propellant gas to cycle the action
The gas port allows a portion of propellant gas to bleed off from the barrel and redirect it to operate the bolt carrier group.
Question 5: In a bolt-action rifle, what is the purpose of the locking lugs?
- To guide the bolt into the receiver
- To lock the bolt securely against the receiver to contain chamber pressure (Correct answer)
- To assist in extracting the spent case
- To prevent the bolt from over-rotating
Correct answer: To lock the bolt securely against the receiver to contain chamber pressure
Locking lugs engage recesses in the receiver to securely lock the bolt in place, safely containing the high pressures generated during firing.
Question 6: What is the purpose of the ejector in a firearm?
- To remove live rounds from the magazine
- To kick the spent case clear of the action after extraction (Correct answer)
- To lock the slide open after the last round
- To feed rounds into the chamber
Correct answer: To kick the spent case clear of the action after extraction
After the extractor pulls the spent case from the chamber, the ejector strikes it to fling it clear of the action.
NRA NRA Firearm Mechanics & Operation 2
What is the primary function of the recoil spring in a semi-automatic pistol?