Sniper Golf Est. 1996 by Sniper's Paradise

 

Ballistic Info

Bullets for Beginners / Dedicated 1000yard Rifle / 175 Vs 168

 

Important Terms:

Ballistic Coefficient:A mathematical factor representing the ratio of the sectional density of a bullet to its coefficient of form. Simply put, BC expresses a bullet's length ( relative to diameter ) and aerodynamic shape, thus indicating its ability to overcome air resistance in flight. The higher its BC factor, the better a bullet retains its velocity and energy, and the flatter its trajectory. Most bullets have BCs between .100 and .700. Higher BCs are required for long-range shooting.

Ballistics:

The science that deals with the motion and flight characteristics of projectiles. It can be divided into three phases:
1) Internal ballistics
2) Exterior ballistics
3) Terminal ballistics
The main aspects of ballistics that concern the rifleman are bullet velocity, stability, kinetic energy, trajectory and penetration/wounding effect.

Boat Tail: Name given to a bullet type with tapered base. Also taper heel

Click: One adjustment of the windage and elevation turrets on a riflescope. The distance one click changes the point of impact depends on the minute of angle rating of the riflescope. Example, a scope with a 1/4" click adjustment would change the point of impact approximately 1/4" at 100 yards.

Drift: In exterior ballistics, the deviation of a projectile from the line of departure due to its rotation or spin. Also commonly applied to the effects of wind. See wind deflection.


Drop: Term used to describe the measure of a bullet's fall after it crosses the line of sight for the second time, i.e., beyond the zero or sighted-in range, due to the effect of gravity.

Effective Range: The range in which a competent and trained individual using the firearm has the ability to hit a target sixty to eighty percent of the time. This ability to hit the target is effected by the length of the barrel of the firearm, the actual cartridge fired, and quality of construction. In reality, most firearms have a true range much greater than this but the likely-hood of hitting a target is poor at greater than effective range. In the firearm lists, the effective ranges are based on personal knowledge and palladium books materials. There seems to be no good formula for the effective ranges of the various firearms.

Energy: The capacity of a mass, body or object to do work. (Terminal Performance; Greg G. Glover,2004)

Foot-Pound: Foot-pound force (ft.-lbf. the f is in italics);is the unit for energy which comes from the English system of measure. Foot-pound force as a value of energy is based on the Standard acceleration of gravity 32.1739 feet per second per second (of feet per second squared):Which is the earths ability to attract a mass at that rate.

FPS: feet pre second, the way velocity is usually measured for the projectile

Freebore:the unrifled section of the bore immediately ahead of the chamber

Grain: used to measure bullets and powder, 1/7000 of a pound

Grooves: the spiral part of the bore that is removed from in-between the lands

Hold Over/Under: Changing the point of aim either above or below of the target (without adjusting the sights) to adjust for the trajectory of the pellet.

Inch of Angle: A one inch drop at 100 yards.

Lands: the raised portion of the spiral rifling in a barrel

Load Density: the weight of the powder charge in grains divided by the volume of the cartridge case in grains of water.

Magnum: A cartridge capable of greater power then normal for its bore size.

Max Ordinate: The highest point a projectile travels above the line of sight.

Milliradian: One one-thousandths of a Radian. Scopes with mil-dot reticles, or graduated range-finding reticles are typically calibrated in Milliradians, not in Minutes of Angle as is sometimes thought.

Minute of Angle (MOA): The arc subtended by an angle of one minute (1/60th of a degree) at any range, usually 100 yards. A minute of angle at 100 yards is 1.0471680" - This is called a TRUE minute of angle. Since 1.0471680" is so close to one inch that for all practical purposes it is considered an inch many people just use one inch as the value at 100 yeards - this makes calculations easier and is called a SHOOTER'S minute of angle.

Muzzle Velocity: The speed of a projectile at the muzzle of a firearm - usually measured in feet per second. Industry standard is the velocity measured at 15" from muzzle.

Ogive: The curved forward portion of the bullet.

Point of Aim (POA): The point where the line of sight intersects the flight of the bullet.

Projectile: The bullet when it is in motion.

Rifling: Spiral grooves cut into the bore of the rifle to impart a spin on the bullet.

Twist: The rate of spiral of the grooves of a rifle barrel expressed in length of barrel per revolution.

Velocity: The speed of a projectile expressed as distance per unit time.


Zero: More correctly "zero sight adjustment". That That adjustment of guns' sights that will place a properly aimed shot at the desired point of at some range with a given load, in the absence of wind. The basis from which subsequent sight adjustments are made.

Zero Range: The distance at which the bullet path exactly coincides with the line of sight. Each gun/load combination actually has two zero ranges - one near the muzzle as the bullet rises through the line of sight and another at some greater distance where the bullet descends through the line of sight. Normally it is the second zero range that most shooters recognise.