NRA NRA Ammunition & Ballistics Fundamentals

Question 1

What are the four basic components of a centerfire metallic cartridge?

Accepted Answer

Case, primer, powder, bullet

Answer

A centerfire cartridge consists of a brass (or other metal) case, a primer seated in the case head, propellant powder, and a bullet.

Question 2

What distinguishes a rimfire cartridge from a centerfire cartridge?

Accepted Answer

The priming compound is inside the rim of the case head

Answer

In rimfire cartridges, the priming compound is spun into the hollow rim of the case, struck by the firing pin at the rim rather than a central primer.

Question 3

What is the purpose of the crimp on a cartridge?

Accepted Answer

It secures the bullet in the case and prevents movement during feeding

Answer

Crimping folds or rolls the case mouth into a cannelure or against the bullet to prevent bullet setback during feeding and handling.

Question 4

What does the term 'SAAMI' stand for and why is it relevant to gunsmiths?

Accepted Answer

Sporting Arms and Ammunition Manufacturers' Institute — sets standardized cartridge and chamber specifications

Answer

SAAMI establishes standardized dimensions and pressure limits for cartridges and chambers, ensuring safe interchangeability.

Question 5

What is 'bullet setback' and why is it dangerous?

Accepted Answer

When the bullet is pushed deeper into the case, increasing chamber pressure

Answer

Bullet setback reduces case volume, raising pressure to potentially dangerous levels that can cause case failure or damage the firearm.

(NRA) National Rifle Association Certified Gunsmith Practice Test

(NRA) National Rifle Association Certified Gunsmith Practice Test

NRA NRA Ammunition & Ballistics Fundamentals