RSO Firearm and Ammunition Identification — Questions and Answers
Question 1: Which ammunition type is most commonly prohibited on indoor ranges due to the risk of ricochets and range surface damage?
- Full metal jacket (FMJ) lead-core rounds
- Steel-core or armor-piercing (AP) rounds (Correct answer)
- Hollow-point (HP) rounds
- Lead round-nose (LRN) rounds
Correct answer: Steel-core or armor-piercing (AP) rounds
Steel-core and armor-piercing rounds are prohibited on most indoor ranges because their hardened cores can penetrate or ricochet off steel backstops and baffles, creating serious injury hazards. FMJ lead-core, hollow-point, and lead round-nose rounds are far more commonly permitted.
Question 2: A shooter arrives with a firearm that has an external hammer, a rotating cylinder, and no detachable magazine. What type of action is this?
- Semi-automatic pistol
- Bolt-action repeater
- Single-action revolver or double-action revolver (Correct answer)
- Lever-action carbine
Correct answer: Single-action revolver or double-action revolver
A rotating cylinder that holds cartridges and the absence of a detachable magazine are the defining features of a revolver. The presence of an external hammer indicates it could be single-action or double-action. An RSO must recognize this to apply the correct administrative handling and unloading procedures.
Question 3: What is the primary visual difference between a rimfire cartridge and a centerfire cartridge?
- Rimfire cartridges are always larger in diameter than centerfire cartridges
- Rimfire cartridges have the priming compound in the rim of the case; centerfire cartridges have a primer cup in the center of the base (Correct answer)
- Centerfire cartridges have a colored case; rimfire cartridges have a silver case
- Rimfire cartridges have a pointed projectile; centerfire cartridges have a flat-nosed projectile
Correct answer: Rimfire cartridges have the priming compound in the rim of the case; centerfire cartridges have a primer cup in the center of the base
The key structural difference is primer placement. Rimfire cartridges (e.g., .22 LR) contain priming compound distributed around the inside of the rim. Centerfire cartridges (e.g., 9mm, .45 ACP) have a replaceable primer cup centered in the base. This distinction matters for identifying ammunition and understanding reload policies.
Question 4: A shooter presents a box labeled '12 Gauge 2¾" #8 Shot.' What does the '2¾"' measurement refer to?
- The diameter of the individual pellets in inches
- The overall length of the loaded cartridge
- The chamber length the shotshell is designed for (Correct answer)
- The maximum effective range of the load in tens of yards
Correct answer: The chamber length the shotshell is designed for
The 2¾" refers to the length of the fired (opened) shotshell case, which corresponds to the minimum chamber length required to safely fire it. Loading a 3" shell into a 2¾" chambered shotgun is dangerous. RSOs must understand this to prevent shooters from using shells that exceed their firearm's chamber specification.
Question 5: Tracer ammunition is generally banned on most civilian ranges primarily because:
- Tracer rounds are significantly less accurate than standard ball ammunition
- The incendiary compound in tracer rounds creates a fire hazard, especially on ranges with dry vegetation or flammable backstop materials (Correct answer)
- Tracer rounds violate federal law for civilian possession
- Tracer rounds produce excessive noise that exceeds OSHA hearing safety limits
Correct answer: The incendiary compound in tracer rounds creates a fire hazard, especially on ranges with dry vegetation or flammable backstop materials
Tracer rounds contain a pyrotechnic compound that burns to mark the bullet's path. This burning compound can ignite dry grass, wood, or other flammable materials on or behind a range. The fire hazard — not legality or accuracy — is the primary reason most ranges prohibit them.
Question 6: An RSO notices a shooter attempting to fire what appears to be a 9mm semi-automatic pistol but hears clicking rather than firing. The RSO can see that the ammunition box left behind is labeled '.380 ACP.' What is the most likely issue?
- .380 ACP is a more powerful cartridge and is overpressure for a 9mm chamber
- .380 ACP cartridges may be short enough to partially chamber but will not reliably feed or fire in a 9mm pistol due to dimensional differences (Correct answer)
- .380 ACP and 9mm are completely interchangeable; the problem must be a broken firing pin
- .380 ACP is a rimfire cartridge and requires a different firing mechanism
Correct answer: .380 ACP cartridges may be short enough to partially chamber but will not reliably feed or fire in a 9mm pistol due to dimensional differences
.380 ACP (9mm Short) is slightly shorter in case length than 9mm Luger. While it can partially chamber in some 9mm pistols, it will not reliably feed, headspace, or fire correctly. An RSO must recognize common caliber confusion scenarios to safely intervene and prevent a squib load or other dangerous situation.
RSO Firearm and Ammunition Identification
Which ammunition type is most commonly prohibited on indoor ranges due to the risk of ricochets and range surface damage?