NRA Firearm Repair & Restoration Techniques 5

Question 1

A gunsmith is parkerizing a military-specification rifle. After the phosphate conversion coating is applied, the FINAL required step is:

Accepted Answer

Immersing or saturating the part in oil while still warm to seal the porous coating

Answer

Parkerizing produces a porous surface that must be sealed with oil (applied while the part is warm for best penetration) to provide corrosion resistance and the characteristic matte appearance.

Question 2

When repairing a broken firing pin in a bolt-action rifle, the gunsmith must verify which critical dimension after fitting the new pin?

Accepted Answer

Firing pin protrusion (fall) beyond the bolt face

Answer

Firing pin protrusion that is too short causes misfires, while protrusion that is excessive can pierce primers or cause slam-fires, making this the critical post-fit measurement.

Question 3

A pump-action shotgun's action bars are bent, causing the slide to bind when cycling. The correct repair procedure is to:

Accepted Answer

Remove the action bars, carefully straighten them in a press using a straightening block, and check for twist

Answer

Both action bars must be removed, carefully straightened (and checked for twist as well as bow), and re-installed as a matched pair to restore smooth cycling.

Question 4

During cold rust bluing, the part is carded after each rusting cycle. What does carding accomplish?

Accepted Answer

It removes loose red oxide while leaving the converted black magnetite in place

Answer

Carding with a fine wire card brush removes unconverted red oxide (which would create a rough, weak finish) while the converted black magnetite stays bonded to the steel.

Question 5

A shooter reports that a semi-auto pistol's slide locks back prematurely on a partially loaded magazine. The most likely cause is:

Accepted Answer

An oversized magazine body allowing the follower to tilt and engage the slide stop early

Answer

When the magazine body is loose or the follower tilts due to a worn magazine, the follower can contact the slide stop early and lock the slide back before the magazine is empty.

(NRA) National Rifle Association Certified Gunsmith Practice Test

(NRA) National Rifle Association Certified Gunsmith Practice Test

NRA Firearm Repair & Restoration Techniques 5