Glossary | Damnosus

A

Action: The mechanical part of a rifle that chambers cartridges, fires, and ejects spent cases. Bolt, lever, pump, semi-auto, and break-action are the major families.

Ballistic Coefficient · BC · G1 BC · G7 BC: A single number that describes how well a bullet resists air drag. Higher BC means a flatter trajectory and less wind drift downrange.
Bedding: How tightly the rifle's action sits inside the stock or chassis. Glass bedding, pillar bedding, and full chassis systems all aim for the same result: zero movement between action and rest.
Bipod: A two-legged support that attaches to the front of the rifle, usually at a sling stud, ARCA rail, or Picatinny section. Steady, load it forward into the gun, don't fight it.
Boat Tail: A bullet base that tapers inward toward the rear rather than cutting off flat. The taper reduces base drag and raises ballistic coefficient.
Bolt Action: A rifle action operated by a manually cycled bolt — lift, pull, push, lock. The dominant action type in precision shooting because it's the most consistent and easiest to bed.
Bore: The inside of a rifle barrel — the channel the bullet travels down. Bore diameter is measured between the lands, not the grooves.
Bull Barrel: A heavy-profile rifle barrel with little or no taper from chamber to muzzle. More mass means slower heating, more consistent harmonics, and less point-of-impact shift between shots.

Cartridge: A complete round of ammunition — case, primer, powder, and bullet assembled together.
Cartridge Base to Ogive · CBTO: Distance from the cartridge base to the curve of the bullet's ogive — measured with a comparator that ignores tip variation. More repeatable than OAL.
Cartridge Overall Length · OAL · COAL: Total length of a loaded cartridge from the base of the case to the tip of the bullet. Constrained by magazine length and by how the bullet sits relative to the rifling.
Chamber: The end of the bore where the cartridge sits before firing. Cut to specific cartridge dimensions — a .308 chamber will not accept a .300 PRC cartridge.

Elevation: Vertical adjustment on a scope, or the up/down correction needed for distance. Dialed via the scope's top turret; runs out at the scope-elevation ceiling.
Extreme Long Range · ELR: Shooting beyond roughly 1,500 yards as a discipline of its own — the regime where cartridge choice, scope capacity, and atmospherics start to fight you in real ways.
Extreme Spread · ES: The difference between the fastest and slowest muzzle velocity in a string of shots. Low ES is a foundational signal of a consistent handload.
Eye Relief: The distance between your eye and the rear lens of the scope at which you see the full image. Too close and the scope hits your face under recoil; too far and the image clips.

Field of View · FOV: How wide an area you can see through the scope at a given distance, usually quoted in feet at 100 yards. Lower magnification = wider field of view.
Fluted Barrel: A bull-profile barrel with grooves machined lengthwise along the outside. Cuts weight without giving up much stiffness, and speeds heat dissipation.

Grains · gr: Unit of weight used for bullets and powder. There are 7,000 grains in a pound; a 140-grain bullet weighs about 9 grams.

Lands and Grooves: The raised ridges (lands) and recessed channels (grooves) cut spirally into the inside of a rifled barrel. The lands grip the bullet and spin it as it travels down the bore.
Load Ladder: A load development method where you shoot a series of charges in small increments, watching for accuracy nodes and pressure signs as charge weight climbs.

Magnification: How much closer a scope makes the target appear, expressed as a multiplier. A 5-25x scope ranges from 5x to 25x magnification.
Match Grade: A claim of tighter tolerances than standard production. Real match-grade rifling, ammunition, and primers exist; "match grade" as a logo on cheap gear is just paint.
Mil · Milliradian · MRAD: An angular unit equal to 1/1000th of a radian — about 3.6 inches at 100 yards, or one yard at 1,000 yards. Standard on most European and military precision optics.
Minute of Angle · MOA: An angular unit equal to 1/60th of a degree — roughly 1.047 inches at 100 yards. Most American precision optics dial in 1/4 or 1/8 MOA clicks.
Mirage: The shimmering, wavy distortion you see through a scope on hot ground or above a heated barrel. Mirage carries wind direction and speed information for the shooter who can read it.
Muzzle Brake: A device threaded onto the muzzle that vents propellant gas sideways to reduce felt recoil and muzzle rise. Loud — wear ears, mind the shooters next to you.

Node: In load development, a velocity plateau where the rifle groups particularly well across a small spread of charge weights. The wider the node, the more forgiving the load.

Objective Lens: The forward lens of a scope — the one facing the target. Its diameter in millimeters governs how much light enters.

Parallax: An optical effect where the reticle and the target sit on different focal planes — moving your eye behind the scope shifts the reticle relative to the target.
Primer: The shock-sensitive cup pressed into the base of a cartridge. The firing pin strikes it, igniting the powder.

Recoil: The rearward push you feel when the rifle fires. Heavier rifles and muzzle brakes both reduce felt recoil.
Relative Long Range · RLR: Pushing any caliber to its practical ceiling, defined by your scope's elevation and your wind-read limits — not by raw distance.
Reticle: The aiming pattern inside a scope — crosshairs, dots, or marked subtensions. Mil or MOA reticles let you hold over without dialing.
Rifling: The spiral grooves cut into the inside of a barrel that spin the bullet for gyroscopic stability. Most modern precision barrels are cut, button-formed, or hammer-forged.

Scope · Riflescope · Telescopic Sight: An optical sight with magnification and a reticle, mounted above the bore. The single biggest contributor to long-range accuracy after the shooter.
Scope Elevation Ceiling: The point at which a scope's internal elevation adjustment runs out and the shooter must hold over the reticle instead of dialing.
Sectional Density: A bullet's weight in pounds divided by the square of its diameter in inches. Higher sectional density means more mass behind the bullet's frontal area.
Standard Deviation · SD: A statistical measure of how tightly your shot velocities cluster around the mean. Lower SD predicts smaller vertical dispersion at distance.

Trajectory: The arc a bullet follows from the moment it leaves the muzzle until it hits the target. Gravity bends it downward; wind pushes it sideways.
Trigger Weight: The amount of force required to break the trigger and fire the rifle, measured in ounces or pounds. Precision rifles typically run 1.5-3 lb.
Twist Rate: The distance, in inches, a bullet travels through the barrel for one full rotation. Written as 1:N — a 1:8 twist makes one full rotation every 8 inches.

Velocity: How fast the bullet is moving, measured in feet per second. Muzzle velocity is the speed at the muzzle; downrange velocity is what matters for the hit.

Wind Hold vs Wind Dial: Two ways to correct for wind. Hold means leaving the turret alone and aiming the reticle into the wind by a measured amount. Dial means turning the windage turret to move the reticle, then aiming dead-on.
Windage: Horizontal adjustment on a scope, or the sideways correction needed for a wind reading. "10 mils right" means hold or dial 10 mil for a left-to-right wind.

Zero: The distance at which your scope's reticle and the bullet's flight path coincide. "100-yard zero" means the bullet hits exactly where the crosshair is at 100.