Caliber
Internal barrel diameter in millimeters or inches, followed by case length (e.g. 5.56×45). It defines the cartridge's entire architecture.
Technical reference
Glossary
68 terms · 65 definitions
V₀ — Muzzle Velocity
Projectile speed at the muzzle, measured in meters per second. The starting value for computing energy and trajectory.
ROF — Rate of Fire
Theoretical automatic rate of fire in rounds per minute (rpm). Practical rate is usually lower for control and wear reasons.
MOA — Minute of Angle
Angular unit used to express precision: 1 MOA ≈ 2.9 cm at 100 m, 7.3 cm at 250 m.
MIL / mrad
Milliradian: 1 mrad ≈ 10 cm at 100 m. Standard of military optics and used for the stadiametric rangefinder.
Bullpup
Layout with action and magazine behind the grip: longer barrel in a more compact package, rearward balance. Examples: AUG, Tavor, FAMAS, F2000.
STANAG
NATO Standardization Agreement. The STANAG 4179 magazine is the standard for 5.56×45 NATO rifles (M16, HK416, SCAR-L, Tavor).
Direct gas impingement
Gas system in which gas acts directly on the bolt without an intermediate piston. Lightweight but dirty, typical of the AR-15/M16.
Long-stroke piston
Piston rigidly linked to the bolt carrier (AK type).
Short-stroke piston
Piston independent of the bolt carrier (SVD type).
Blowback / unlocked breech
System where bolt inertia (and sometimes a spring) holds the cartridge in chamber without mechanical lockup. Typical of 9 mm pistols and SMGs.
Rotating bolt
Bolt that rotates a few degrees to lock its lugs into the barrel extension. Strong mechanical lockup used on AK, AR-15, M14.
Roller-delayed bolt
H&K system: two rollers slow bolt opening by exploiting residual gas energy. Used on G3, MP5, HK33.
Telescoping bolt
Bolt that wraps around the barrel breech, reducing overall weapon length. Characteristic of the Uzi and many modern SMGs.
Open bolt
The bolt starts rearward before firing.
Closed bolt
The bolt starts forward before firing.
Striker-fired
Striker-launched system (no external hammer): fewer moving parts, constant trigger weight. Typical of Glock, M&P, Walther PPQ.
DA/SA
Double Action / Single Action: the first round can be fired either by cocking the hammer (SA, short pull) or with a longer trigger pull (DA).
DAO
Double Action Only: every shot requires the same long trigger pull. Common in compact defense pistols and modern revolvers.
Headspace
Distance between the case head in the chamber and the bolt face in closed position. Excess or shortage causes malfunctions and ruptures.
Chamber
Cavity inside the barrel that hosts the cartridge. Its dimensional tolerances are critical for reliability and accuracy.
Rifling (twist rate)
Helical grooves in the bore that stabilize the bullet. Twist rate (e.g. 1:7") is matched to bullet weight.
Picatinny / MIL-STD-1913
NATO standard tactical rail with transverse slots. Allows universal mounting of optics and accessories.
M-LOK
Magpul modular system for handguard accessories: oblong slots and T-nuts. Lighter and more flexible than continuous Picatinny.
KeyMod
Pre-M-LOK standard, now in decline. Quick-attach system using keyhole-shaped slots.
DMR — Designated Marksman Rifle
Squad-level marksman rifle: extends infantry effective range to 600-800 m, semi-auto (e.g. SVD, M14 EBR, HK417).
Light machine gun
Light Machine Gun: sustained-fire squad weapon (e.g. Minimi/M249, RPK, MG4).
Squad automatic weapon
Squad Automatic Weapon: sustained-fire squad weapon (e.g. Minimi/M249, RPK, MG4).
GPMG
General Purpose Machine Gun: tripod-or-bipod machine gun in full-power caliber (7.62 NATO). Examples: MG3, M240, PKM.
PDW
Personal Defense Weapon: compact firearm between SMG and carbine for vehicle crews and support personnel (e.g. P90, MP7).
Full metal jacket
Full Metal Jacket: brass-jacketed projectile.
Hollow point
Cavity-tip projectile that expands in tissue, transferring energy.
Subsonic
Cartridge with velocity below the speed of sound (≈ 340 m/s). Designed for suppressed use, eliminating the sonic crack.
Suppressor (silencer)
Muzzle device that reduces noise and flash by slowing gas expansion. Does not silence the weapon: it tames the bang.
Flash hider
Disperses hot gases to reduce visible flame.
Muzzle brake
Redirects gases to reduce recoil rise.
Cook-off
Spontaneous detonation of a chambered round caused by residual barrel heat after long bursts. Main concern with closed-bolt designs.
Armor piercing
Armor Piercing: steel-cored projectile.
Armor piercing incendiary
Armor Piercing Incendiary projectile.
Tracer
Pyrotechnic compound used to visualize the projectile trajectory.
Red dot
Non-magnifying holographic/reflex optic with illuminated red dot. Designed for rapid engagement at short range (within 200 m).
LPVO
Low Power Variable Optic: variable low-magnification scope (e.g. 1-6×, 1-8×). Combines red-dot speed with mid-range target ID.
FOV — Field of View
Width of the area visible through an optic, measured at 100 m. Higher FOV means faster target acquisition.
Parallax
Aiming error caused by eye position relative to the reticle. Parallax-free optics cancel the effect at a specific distance.
Eye relief
Optimal distance between shooter's eye and ocular lens. Critical on high-recoil calibers to avoid scope bite.
BDC — Bullet Drop Compensator
Reticle or turret that compensates bullet drop at various ranges, calibrated for a specific cartridge.
Zeroing
Procedure of aligning optic/sights so point of aim matches point of impact at a chosen distance (e.g. 100 m, 200 m, 50/200 yd).
Charging handle
Cocking lever used to chamber the first round and for clearing. On AR-15 it is non-reciprocating rear; on AK it is side-mounted and reciprocates with the bolt.
Cyclic rate
Maximum mechanical rate of fire.
Sustained rate
Practical long-term rate without overheating the barrel.
Anti-tank guided missile
Squad or vehicle weapons against tanks and bunkers. Examples: Javelin, Kornet, Spike, TOW, NLAW.
Man-portable air-defense system
Shoulder launchers against helicopters and low-altitude aircraft. Examples: Stinger, Igla, Mistral.
Surface-to-air missile
Vehicle, ship or fixed-site air defense systems. Examples: Patriot, S-400, Aster 30, SAMP/T.
Ballistic missile
A missile with high-altitude ballistic flight. Examples: Iskander-M, DF-21, Minuteman III, DF-41.
Cruise missile
Atmospheric turbojet or ramjet flight with a programmed trajectory; land-attack or anti-ship. Examples: Tomahawk, Kalibr, Storm Shadow, BrahMos, Exocet, Harpoon.
Circular error probable
The radius within which 50% of shots land.
Medium-altitude long-endurance
Medium-altitude / long-endurance size class for unmanned systems.
High-altitude long-endurance
High-altitude / long-endurance size class for unmanned systems.
Combat UAV
Combat UAV, an armed category of unmanned vehicles.
Unmanned surface vehicle
Surface category of unmanned vehicles.
Unmanned underwater vehicle
Underwater category of unmanned vehicles.
Naval systems
Naval combat units: aircraft carriers, cruisers, destroyers, frigates, attack and ballistic-missile submarines, amphibious and assault ships.
Electronic warfare
Systems that fight in the electromagnetic spectrum: frequency jammers, surveillance and tracking radars, signals intelligence, infrared countermeasures and counter-UAS.
Space systems
Military space capabilities: reconnaissance and SIGINT constellations, communication and navigation satellites, early-warning systems, anti-satellite weapons.
Anti-satellite
Anti-satellite weapons are included in the site's military space capabilities.
Sonar
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Electronic support measures
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Low Earth orbit
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