Ballistics Flashcards
What type of primers does the US Army use?
Boxer
What is the name for the tip of a bullet?
Miplat
What effect on muzzle velocity will shortening the barrel by two (2) inches have on a 7.62x51mm weapon?
-50fps (-25 feet per second for every inch removed)
What is causes Spin Drift?
The rotation of the bullet imparted by rifling (Gyroscopic Stability)
What part of the barrel erodes/degrades the fastest?
The throat of the barrel (close to the chamber)
Using an insufficient Twist Rate for a bullet will cause what negative effect?
Unstable Bullet (pitch/yaw) due to a lack of rotational inertia
At what point in a bullets trajectory does it real it’s Maximum Ordinate?
55 percent (55%) of the target range.
E.g. range of 800m
800/2 = 400
400 + 10% = 440m
What is the formula for calculating the speed of sound on a given day, accommodating for temperature?
1061fps + temperature (in F)
E.g daily temperature of 50 degrees
1061 + 50 = 1111fps
What effects gun propellent the most?
Temperature
What is the G1 Ballistic Coefficient (BC) for M118LR ammunition?
.475
What is the definition of a Ballistic Coefficient?
A Ballistic Coefficient is a measure of how well the bullet penetrates the air
What three factors make up the Ballistic Coefficient (BC)?
Bullet weight, Cross Sectional Area (diameter), and Form Factor
How does the Coriolis Effect effect a bullet shot in the southern hemisphere’s horizontal movement?
The bullet will impact LEFT of target
What drift can a one (1) degree cant induce at 1000m?
Five (5) inches at 1000m
Speed of bullet in Supersonic phase
> Mach 1.2
