RSO Firearm Stoppages and Malfunctions 5 — Questions and Answers
Question 1: An RSO observes a shooter's revolver cylinder binding and refusing to rotate after live firing in sandy conditions. What is the most likely cause?
- Improper cylinder gap
- Debris or fouling accumulation around the cylinder axis or crane preventing rotation (Correct answer)
- An oversized bullet diameter
- A broken hand (cylinder-rotating pawl)
Correct answer: Debris or fouling accumulation around the cylinder axis or crane preventing rotation
Sand, grit, or fouling around the cylinder crane or axis pin can bind cylinder rotation; thorough cleaning resolves this environmental malfunction.
Question 2: During a carbine course, a shooter's AR-15 goes fully into battery but fails to fire when the trigger is pulled. The primer shows a light strike mark. What should the RSO first suspect?
- A bent firing pin
- A worn or broken hammer spring or debris obstructing the firing pin channel (Correct answer)
- A defective barrel
- Incorrect buffer weight
Correct answer: A worn or broken hammer spring or debris obstructing the firing pin channel
Light primer strikes in AR-pattern rifles are commonly caused by a weakened hammer spring or carbon fouling restricting firing pin travel.
Question 3: Which condition describes a firearm that continues firing after the trigger is released on a semi-automatic platform?
- Hang-fire
- Slam fire or runaway condition (Correct answer)
- Double-feed
- Cycling malfunction
Correct answer: Slam fire or runaway condition
A runaway or slam-fire condition occurs when the disconnector fails to hold the hammer, causing continuous fire independent of trigger release.
Question 4: A shooter on the range has a semi-auto pistol with the slide locked back but the magazine still has rounds. What should the RSO identify as a potential cause?
- Overpressure round
- The slide stop was inadvertently engaged by the shooter's thumb during firing (Correct answer)
- A broken ejector
- Incorrect magazine caliber
Correct answer: The slide stop was inadvertently engaged by the shooter's thumb during firing
High-grip shooters often place their thumb on or near the slide stop, which can prematurely lock the slide back before the magazine is empty.
Question 5: After a cease-fire is called due to a range malfunction, when should the RSO allow shooters to handle their firearms to clear malfunctions?
- Immediately after the cease-fire command
- Only after the RSO has assessed the situation and determined it is safe to proceed (Correct answer)
- After a mandatory 60-second wait
- Only after all other shooters have left the line
Correct answer: Only after the RSO has assessed the situation and determined it is safe to proceed
The RSO must evaluate the nature of the malfunction before permitting firearm handling to ensure no hangfire or other hazard is present.
Question 6: An RSO finds that a particular magazine brand consistently causes failures to feed in multiple shooters' identical pistols. What corrective action should the RSO take?
- Have shooters adjust their grip
- Remove the suspect magazines from use and document the failures (Correct answer)
- Clean all firearms involved
- Replace the barrel on all affected pistols
Correct answer: Remove the suspect magazines from use and document the failures
Magazines that consistently cause malfunctions across identical firearms indicate a magazine defect and should be removed and documented for safety.
Question 7: A shooter's semi-auto rifle chambers a round but the bolt does not fully close, leaving a small gap. What is the RSO's primary safety concern?
- The round may be wasted
- Firing out of battery can cause case head separation and hot gas venting into the action (Correct answer)
- The magazine may fall out
- Accuracy will be reduced
Correct answer: Firing out of battery can cause case head separation and hot gas venting into the action
Firing a cartridge when the bolt is not fully locked (out of battery) risks case head separation and exposes the shooter and bystanders to high-pressure gas.
RSO Firearm Stoppages and Malfunctions 5
An RSO observes a shooter's revolver cylinder binding and refusing to rotate after live firing in sandy conditions.
What is the most likely cause?