NRA Firearm Inspection & Testing Procedures Flashcards

What is 'trigger overtravel' and how does a gunsmith check for it?

Answer: The movement of the trigger after the sear releases the hammer or striker — checked by feel and measured with gauges or observation

Overtravel is trigger movement after the sear breaks — excessive overtravel can disrupt aim; gunsmiths check it by feel and can measure it with a dial gauge.

What does inspecting the 'forcing cone' of a revolver barrel involve, and why is it important?

Answer: Examining the tapered entry of the barrel for cracks, erosion, or out-of-spec dimensions that affect bullet transition from cylinder to bore

The forcing cone guides bullets from the cylinder into the bore, and cracks, erosion, or incorrect angles cause leading, pressure loss, and accuracy problems.

What is 'trigger creep' and how does it differ from overtravel?

Answer: Creep is undefined travel and takeup before the sear breaks; overtravel is movement after the sear releases

Trigger creep is the mushy, undefined movement before the sear breaks, while overtravel is the movement after — both can negatively affect accuracy.

What does a gunsmith look for when inspecting a semi-automatic pistol's feed ramp?

Answer: Wear patterns, gouges, burrs, or incorrect angles that could impede reliable cartridge feeding

Feed ramp defects — burrs, incorrect angles, or rough surfaces — cause feeding failures, and identifying the pattern of wear helps diagnose reliability issues.

When performing a safety inspection on a used bolt-action rifle, what should be checked regarding the trigger sear engagement?

Answer: That the sear has adequate engagement depth to prevent accidental firing, especially when the safety is disengaged or the bolt is closed forcefully

Insufficient sear engagement can allow the rifle to fire without a trigger pull, especially after rough handling — a critical safety concern requiring adjustment or repair.

What is a 'borescope' and why is it valuable in gunsmithing?

Answer: A small camera or optical instrument inserted into the bore for detailed visual inspection of the rifling, throat, and crown

A borescope allows the gunsmith to visually inspect the full length of the bore for erosion, pitting, fouling, cracks, or obstructions without disassembly.