NRA Ammunition & Ballistics Flashcards

What is the term for the pressure spike that occurs when the bullet first begins to move from the case?

Answer: Chamber pressure

Chamber pressure is the pressure generated inside the cartridge case when the propellant ignites, typically measured in PSI or CUP at its peak just as the bullet begins moving.

What is the purpose of a cannelure on a bullet?

Answer: To provide a groove for case crimping to prevent bullet setback

A cannelure is a groove around the bullet's shank that allows the case mouth to be crimped into it, preventing bullet setback during feeding.

What does the term 'muzzle velocity' refer to?

Answer: The speed of the bullet as it exits the barrel

Muzzle velocity is the speed of the projectile measured at the point it exits the muzzle of the barrel, typically measured in feet per second (fps).

What is a soft-point (SP) bullet designed to do upon impact?

Answer: Expand its diameter to create a larger wound channel

A soft-point bullet has an exposed lead tip that initiates controlled expansion upon impact, increasing diameter while retaining weight for effective energy transfer.

What is the difference between .357 Magnum and .38 Special cartridges in terms of chamber compatibility?

Answer: .357 Magnum firearms can fire .38 Special, but .38 Special firearms cannot safely fire .357 Magnum

Because .357 Magnum is longer and higher pressure, a .357 Magnum firearm can safely fire .38 Special, but a .38 Special firearm must never be used with .357 Magnum.

What is the primary purpose of a full metal jacket (FMJ) bullet?

Answer: Consistent feeding and reduced barrel fouling without expansion

FMJ bullets have a lead core enclosed in a harder metal jacket that promotes reliable feeding, reduces bore fouling from lead, and does not expand on impact.