As with most specialized endeavors the shooting community has its own language. MOA, grains, rimmed or rimless, ogive and metplat all describe something and have their meanings.
Use Ballistics in a Sentence …”
Take the term ‘ballistics’ for example. On the criminal ‘who done its’ this is the artifacts left when a cartridge is fired. Technically these are tool marks not ballistics. Internal ballistics is a study of what goes on inside the weapon. It includes the action, trigger and striker/hammer combinations as well cartridge characteristics. Note that the bullet is the projectile and the case, primer, powder and bullet when assembled is a cartridge, not bullets. Lock time is the interval from the trigger’s release of the sear until the firing pin hits the primer. The sear holds back the hammer or striker when the gun is cocked. In modern weapons, this is of little more than an academic discussion and is measure in milliseconds. But if you have ever noticed there is a discernable time interval when the flint of a flintlock when the flint strikes the frizzen igniting the powder in the pan, which in turn lights the internal charge firing the bullet.
Subsonic, Supersonic & Suppressors
Subsonic, below the speed of sound, about 1050-1100 feet per second, projectiles create no shock waves, supersonic, usually rifles, above this speed you can detect a ‘crack’ as the shock wave, a mini sonic boom, passes you by. But with the muzzle blast suppressed you can’t locate the shooter’s position, you know you’re being shot at, but not from which direction. Also, the brain may only react to a suppressed handgun on a subliminal level, not realizing a gun is being fired. So tactically speaking suppressors have their place.
Transitional Ballistics Definition
Transitional ballistics is what goes on in the first few millimeters from the muzzle when the bullet enters true independent flight, no longer influenced by the guns barrel. Muzzle breaks, barrel crowns and flash hiders. Oh, by the way, flash hider hides or minimizes the flash from the shooter, not every else. Some would include suppressors, i.e. ‘silencers’ in this category. Suppressor, is the preferred technical term as the guns muzzle blast is suppressed not silenced. Generally, it is this muzzle blast the gives away the shooters position. In long, long range shooting it is possible that the supersonic bullet will slow to below sonic, or the speed of sound. Mach 1 is the speed of sound for that media, in our case usually air, as mentioned this is about 1100 feet per second. Between Mach 1.2 and .8 is the transitional velocities. As the bullet slows the center of pressure moves forward affecting the stability of the projectile.
External ballistics, is the study of projectiles in flight, and includes rocket propelled ballistic projectiles. Ballistic when applied to powered projects, rockets and missiles, aimed at a target, are ‘dumb’ without any midcourse correction and proceed like an unguided bullet. Bullet shape, weight and materials are what affect projectile flight characteristics. Krupp, the German arms company, defined the standard projectile as being 3 calibers long with a 2 caliber radius at the point and a 1.7 caliber bearing surface. Caliber is the diameter of the projectile or bullet. By defining the standard all other projectiles can be compared to it, giving the ballistic coefficient (drag coefficient for the aircraft guys and gals, ballistic coefficient for us shooters). Ballistic coefficient has a component value called sectional density. This is the diameter squared divided into the bullets mass. Again, the term is mass not weight. Weight is mass in a gravitational field, mass times the acceleration due to gravity is weight. Gram and kilogram are terms of mass. Pounds and grain is weight, with 7000 grains to a pound.
Terminal ballistics is concerned with bullet structure, design and effect on striking the target. Handgun, wad cutter bullets punch nice round holes in paper targets and are the tradition flat on both ends, bullets. Expanding bullets expand, fragment and cause havoc inside of living organisms. Terminal ballistics concerns itself with what happens when the bullet strikes the target, paper, wood, metal or flesh. In hunting and self-defense, the goal is to disrupt the plumbing and data lines, i.e. blood vessels and the central nervous system.
Custom Shooting Ranges
From this short introduction to gun and ammunition terms it is apparent that there is a ‘language’ unique to the shooter. Shooting Range Industries offers custom shooting ranges and shooter would be proud of! Contact us to learn more today.