Firearm Repair & Restoration Techniques Flashcards

When re-crowning a rifle barrel, which tool is most appropriate for producing a target-grade recessed crown?

Answer: 11-degree carbide cutter with a pilot

An 11-degree carbide cutter with a pilot centers itself in the bore and cuts a consistent, precise recessed crown that protects the rifling and improves accuracy.

A revolver exhibits cylinder timing issues where the cylinder does not lock up fully before the hammer falls. Which component is the MOST likely cause?

Answer: Cylinder hand (pawl)

The cylinder hand (pawl) advances and indexes the cylinder; wear on its tip or engagement surface causes the cylinder to under-rotate and fail to lock up in time.

What is the correct procedure when using a barrel vise and action wrench to remove a stubborn barrel from a rifle action?

Answer: Clamp the barrel firmly in the vise and rotate the action wrench counter-clockwise when viewed from the muzzle

Standard barrel threads are right-hand, so the action (receiver) must be turned counter-clockwise (when viewed from the muzzle) to unscrew it from the barrel.

During stock refinishing, a gunsmith discovers checking that has been partially filled with old finish. The best method to restore crisp, sharp checking is to:

Answer: Use a single-cut checkering file to deepen and clean out the grooves, then re-run border lines

A single-cut checkering file is run through each groove to remove old finish and re-define the diamonds before re-cutting the borders.

A semi-automatic pistol consistently fails to feed the last round from a magazine. The most logical first diagnostic step is to:

Answer: Inspect and measure the magazine follower angle and spring tension

Last-round feed failures most often result from a weak or canted magazine follower that does not present the final cartridge at the correct angle for the slide to chamber it.

Which rust bluing step is responsible for converting the initial red iron oxide into the desired black magnetite (Fe3O4)?

Answer: Boiling the part in distilled water

Boiling the rust-coated part in distilled water converts the red ferric oxide (Fe2O3) to black magnetite (Fe3O4), which is the durable rust-blue finish.

A bolt-action rifle has excessive headspace confirmed by gauge. Which repair approach is most appropriate before condemning the barrel?

Answer: Set the barrel back one thread and re-cut the chamber

Setting the barrel back one thread shortens the chamber enough to reduce headspace to within specification, which is far more practical than replacing the barrel.