by Anthony G Williams
AA anti-aircraft
accelerator a pivoting lever inside a short-recoil mechanism
which acts to accelerate the rearward movement of the bolt
ACR advanced
combat rifle: a competition held in the USA in the late 1980s
ACSW Advanced Crew Served Weapon (formerly OCSW); US 25mm AGL, designated XM307
AGL automatic grenade launcher (aka GMG)
AHEAD Advanced Hit Efficiency and Destruction (a proprietary
Oerlikon ammunition development)
air-cooled a weapon which achieves barrel cooling by radiation
direct to the atmosphere
ammunition collective name for cartridges (or equivalent)
AP armour piercing; a projectile designed to penetrate
armour, or a cartridge loaded with such a projectile
APC(BC) armour piercing, capped, (ballistic capped): an
AP shot with a softer cap to aid penetration of face-hardened
armour (and a streamlined cap to reduce air resistance)
APCR armour piercing, composite, rigid: shot consisting
of a penetrating core (usually of tungsten alloy) enclosed within
a light-alloy body, which travels as a unit to the target
APDS armour piercing, discarding sabot: similar to APCR
except that the body (which may be light alloy or plastic) breaks
up and falls away from the penetrating core when the shot leaves
the muzzle.
APFSDS armour piercing, fin stabilised, discarding sabot:
similar to APDS except that the penetrating core is long and narrow
and is stabilised in flight by fins
APHC armour piercing, hard core: an alternative designation
for APCR
APHE armour piercing high explosive
APHHW All-purpose
hand-held weapon: USA project 1959-62
API armour piercing incendiary: a dual-purpose projectile
API blowback advanced primer ignition blowback: a type
of automatic mechanism
APSV armour piercing super velocity; British term for Littlejohn
squeezebore ammunition (also initially used to describe APDS)
arrowhead shot APCR with reduced-diameter alloy body in
centre
assault rifle
a military rifle offering selective fire (both full and semi-automatic) with an
effective range of at least 300 metres, and normally firing a cartridge
intermediate between pistol/SMG rounds and full-power rifle/MG rounds of 7.62mm
(or similar) calibre
AT anti-tank
automatic a weapon which continues to fire and reload automatically
for as long as the trigger or firing button is pressed
B added to a cartridge designation to identify a belted
case (e.g. 20x105B)
ball (round) a small arms projectile or bullet, i.e. not
AP, I, HE, or T
ballistics the science concerning the passage of a projectile
from the instant of firing to the end of its flight
ballistic cap a streamlined (usually light alloy) nose
cone used to improve the ballistic coefficient of a blunt projectile
ballistic coefficient a factor which measures the aerodynamic
drag of a projectile and therefore the rate at which it loses
the velocity: the higher the number, the lower the drag
barrel the tube connected to (or integral with) the chamber,
down which the projectile is accelerated
barrel extension the part of the barrel which extends behind
the chamber, usually to accommodate a locking mechanism
base bleed a projectile which contains a slow-burning chemical
in the base in order to reduce air resistance and extend range
base fuze a detonating fuze fitted to the base of an HE
shell
battery a gun is "in battery" when it is at rest
in a forward position in the mounting (i.e. not recoiling)
bayonet-a
short knife or spike for fitting to a rifle barrel; it may be detachable or
folding
BB see base bleed
BC ballistic
coefficient: an indicator of the aerodynamic efficiency of a cartridge
belt (1) a raised strip around a cartridge case, in front
of the extractor groove. (2) a strip of fabric or (more usually)
metal, into which cartridges are fitted to facilitate feeding
them into a weapon. Metal belts may be disintegrating, non-disintegrating
or a continuous loop
belted case a cartridge case with a raised section in front
of the extractor groove to aid location in the chamber
belt feed the use of a belt to supply ammunition to a gun
mechanism
belt link a piece of metal which constitutes a part of
a belt
bipod a
two-legged support fitted to the forward end of a gun, for accurate firing in a
prone position
BK Bordkanone (German): a large-calibre airborne cannon
blank a cartridge which has a primer and propellant but
no projectile
blowback a type of automatic weapon operating mechanism
bolt a part of the operating system, containing the firing
mechanism, which slides in line with the barrel, pushing a cartridge
into the chamber and holding it there during firing
bolt carrier part
of the action, which contains the bolt and reciprocates with it. It begins to
move before (and finishes moving after) the bolt because its task is to unlock
and lock the bolt to the barrel
bolt group the bolt assembly, including the firing pin/hammer and other items which are attached to the bolt
bolt lugs protrusions from the bolt, which are used to lock it to the barrel extension or receiver
bolt stop the part of the receiver which stops the bolt's rearwards movement
bore the inside of the barrel
bottlenecked cartridge a cartridge with a case whose diameter
reduces sharply to the neck, creating a shoulder
bourrelet shell bodies are usually made slightly smaller than the bore,
except for a slighter wider part which is carefully machined to fit - this is
known as the bourrelet
box magazine a type of magazine in which the cartridges
are stacked on top of each other (they may be single or double
stacked)
Brandgranate (German): incendiary shell
Brandspreng-granate (German): high explosive/incendiary
shell
breech the opening at the rear of the chamber which allows
cartridges to be loaded and fired cases extracted
breechblock alternative term for bolt, normally used when
its operating movement involves pivoting, or sliding vertically
or horizontally
breech face the part of the barrel surrounding the breech
BRL Ballistics
Research Laboratory: at US Army, Aberdeen
bullet see ball
bullpup design a rifle in which the action and magazine
are behind the trigger
burst fire a
control which fires a defined number of rounds (usually two or three) for each
press of the trigger
butt the back face of the rifle, which is held against the shoulder on firing
buttstock the back part of the rifle, from the receiver to the butt
calibre (1) the diameter of a projectile, or of the inside
of a barrel. (2) designation of the cartridge a weapon is designed
for
calibre length the barrel length divided by the calibre,
usually prefixed with "L"; e.g. a 40mm L/70 indicates
a barrel (40x70=) 280 cm long
cannelure a groove around a small-arms bullet for receiving
a crimp
cannon (modern) a large-calibre fast-firing automatic weapon,
generally taken to be between 20mm and around 57mm calibre
cartridge a unit or round of ammunition, normally comprising
the cartridge case, projectile, propellant and primer
cartridge case the part of the cartridge which contains
the propellant and holds the projectile and primer firmly in place
caseless ammunition ammunition which does not have a cartridge
case but uses solid propellant to hold the projectile and primer
centrefire cartridge fired by a primer located in the centre
of the head
chain gun an externally-powered automatic weapon which
uses a chain to drive the operating cycle
chamber the space at the rear of the barrel in which the
cartridge is positioned and supported during firing
chemical fuze a contact fuze on an HE shell which operates
by percussion
chromium plating used to protect the barrel bore and chamber
CIWS close-in weapon system; a naval short-range AA/anti-missile
system, usually with automatic aiming and firing
clip a piece of metal which holds together several cartridges
(normally by the case heads) for feeding into a weapon; or several
cartridges held together by a clip
closed bolt an automatic weapon designed to commence the
firing cycle with the cartridge already loaded into the chamber
(see open bolt)
closed loop a CIWS control system which uses radar to track
both target and projectiles and corrects the aim accordingly
coaxial mounting a means of mounting a secondary gun in
parallel with a primary gun so that both weapons can be aimed
using the same sights
combustible case a cartridge case which is designed to
burn with the propellant
compensator a
type of muzzle attachment for hand-held weapons, in which all of the diverted
gas is directed upwards to resist muzzle rise
contact fuze a fuze which is initiated by impact with the
target
cook-off the unwanted ignition of a cartridge by heat in
a gun chamber
cordite a type of propellant
counter-recoil a type of gun mounting in which the gun
is fired as it returns to battery, so the initial recoil force
is expended in arresting the forward movement of the gun. See
floating mounting and soft recoil
cowling mounting an automatic weapon mounted in the cowling
of a propeller-driven fighter and synchronised to fire through
the propeller disc
CQB close-quarter
battle: especially urban fighting
crimp a depression in the neck of a cartridge case, intended
to hold the projectile firmly in place prior to firing
CTA cased telescoped ammunition: in which the projectile
is contained with the cartridge case (which is often combustible)
dark trace the initial burn of a tracer, designed to give
no light
deflection the angle between the position of a crossing
target (usually an aircraft) and the required aiming point, which
will be ahead of it
delayed blowback a
hybrid gun mechanism in which the bolt is locked to the barrel on firing, is
then unlocked by the mechanism, but relies on blowback for the remainder of the
firing cycle (see retarded blowback)
detonation the explosion of an HE projectile
dioptre sight (American
- 'diopter') a type of rearsight which provides a small hole through which the
shooter looks at the foresight
disintegrating link a type of ammunition belt consisting
of metal links, which fall apart as each cartridge is chambered
double base a type of propellant
drill round a cartridge which is totally inert, used to
practice loading and unloading drills. It is always made easily
recognisable
driving band a strip of soft metal or plastic around a
projectile, which is intended to be gripped by the rifling in
order to induce spin
drum a type of circular magazine in which the cartridges
are held parallel to each other (sometimes used to describe a
pan magazine); see helical drum and pan magazine.
DU depleted uranium; a heavy metal used in some AP shot
dual belt feed a gun with two belt feeds, each usually loaded with a
different type of ammunition
dummy round a cartridge which is completely inert (i.e.
no primer or propellant)
duplex loading a cartridge loaded with two full-calibre
projectiles, intended to follow each other down the barrel (see
multiball, triplex)
ejection the act of throwing an extracted cartridge case
clear of the gun
electric ignition a method of igniting cartridges by passing
an electrical current through the primer
electromagnetic gun a gun which uses electromagnetic force
to accelerate a projectile (also known as a rail gun)
electrothermal-(chemical) a system which uses a plasma
generator instead of a primer
elevation the movement of a gun in its mounting through
a vertical arc
ER extended range
ERFB(BB) extended range, full bore (base bleed)
erosion wear on the inside of a barrel caused by hot propellant
gasses and friction generated by projectiles
external or exterior ballistics the science of projectile flight from
the muzzle of a gun
extended chamber see hooded chamber
externally powered a gun mechanism which requires an external
source of power to operate; this is usually electric but may be
hydraulic or manual, or in aircraft powered by engine gas or the
slipstream
extraction the act of pulling a fired cartridge case from
the chamber
extractor claw a hook, attached to the bolt, which fits
into the extractor groove in order to pull the cartridge out of
the chamber
extractor groove a groove around the head of a cartridge
case, into which the extractor claw fits
FABRL USA
ammunition project: originally Frankford Arsenal + BRL, then 'future ammunition
for burst rifle launch'
FAPDS frangible armour piercing discarding sabot
feed the method of delivering ammunition to the gun
FCAR full-calibre
assault rifle; one firing an intermediate cartridge with a calibre the same as a
full-power rifle/MG round (i.e. 7.62 or 7.92 mm)
feed the method of delivering ammunition to the gun
FGB Flächengondelbewaffnung (German) an aircraft gun
pod
fin stabilised a projectile whose flight is stabilised
by fins rather than by being spun by rifling
firing cycle the sequence of loading, firing, extracting,
ejecting and reloading
firing pin a spring-loaded steel pin which strikes a primer
to cause ignition
FlaK Fliegerabwehrkanone (German) AA artillery; also sometimes
given as Flugabwehrkanone or Flugzeugabwehrkanone
flash hider
a cone-shaped device fitted to the muzzle to screen the muzzle flash from the
firer
flash suppressor a device fitted to the muzzle to reduce the flash from burning propellant
flat trajectory the flight of a projectile which involves
minimal drop due to gravity; associated with high velocity
flechette a
long, thin bullet, which is fin-stabilised and (in small arms) contained within
a sabot for firing
flexible mounting a simple, unpowered gun mounting in which
the gun can be moved in traverse and elevation by the gunner's
hands
floating firing see counter-recoil
floating mounting see counter-recoil
fluted chamber longitudinal grooves in the chamber to permit
gun gas to seep back around the cartridge case to prevent it from
sticking
FMPDS frangible missile-piercing discarding sabot
folding stock a
buttstock which is can be folded to lie alongside the rifle
fore grip-the grip under the barrel for the forward (non-firing) hand
FPAR full-power assault rifle; a selective-fire rifle chambered for the 7.62 x 51 NATO or other full-power rifle/MG cartridge
fragment when a bullet breaks up under the stress of impact and tumbling it is said to fragment
frangible a projectile designed to break up on hitting
the target
full-calibre a projectile which fills the bore of a gun
(see sub-calibre)
fuze a device for initiating the detonation ofn an HE shell
gas operated a type of gun mechanism using gas tapped from
the barrel to drive the firing cycle
gas regulator a
valve on a gas-operated weapon which regulates the amount of gas tapped to
operate the action, according to circumstances
gas-unlocked blowback a type of gun mechanism using gas
tapped from the barrel to unlock the breechblock; the remainder
of the firing cycle being blowback
Gast a type of twin-barrel automatic gun mechanism
Gatling an early type of manually powered rotary gun; sometimes
used to refer to any rotary weapon
GAU (American): Gun Aircraft Unit
Glimmspur (German): often written Gl'spur; a dimly glowing
tracer for night use
GMG Grenade Machine Gun (aka AGL)
GPMG general purpose machine gun
grain measure of weight used in UK and USA for propellant
charges and (in smaller calibres) projectiles. 1 gram = 15.432
grains
gravity feed the use of gravity to supply ammunition to
the gun mechanism
grenade launcher a low-velocity gun designed to fire small
HE projectiles
grooves the larger interior diameter of a rifled barrel;
between the lands
gun gas gas generated by ignition of the propellant in
a cartridge
gun pod a detachable pod, containing a gun (or guns) and
ammunition, which is carried by aircraft
gyro gunsight a simple type of lead-computing gunsight
to aid deflection shooting
hammer-a
part of a trigger mechanism which pivots under spring pressure to strike the
firing pin
hand grip or guard-the part of the rifle intended to be held by the firer's supporting (as opposed to trigger) hand
hang fire a delay in the ignition of a cartridge after
the primer has been struck
Hartkernmunition (German, WW2) an APCR shot used in aircraft
cannon
HC high capacity; a shell with an unusually large (HE)
capacity
HE high explosive; the normal filling of cannon shells
head the rear of the cartridge, into which is fitted the
primer
headspace the accurate location of a cartridge in the chamber
ready for ignition
headstamp information about the cartridge, stamped into
the head
HEAT high explosive, anti-tank; (see hollow charge)
heavy machine gun a machine gun with a calibre significantly
larger than a military rifle cartridge but smaller than a cannon;
in effect, 12.7-15 mm
HEDP high-explosive dual-purpose; a modern projectile which
combines hollow-charge with general HE effect
helical drum a magazine in which all rounds point inwards,
following a spiral track
high-angle mounting a mounting which permits a weapon to
be elevated at or close to the vertical for AA fire
HMG heavy machine gun
hollow charge an explosive projectile with a cone-shaped
hollow, lined with metal, in the nose, which generates an intense
armour-piercing jet
hooded chamber a chamber which is longer than necessary
to contain a cartridge; associated with API blowback designs
housing-encloses
part of a gun action
HV high velocity
HVAP high velocity, armour piercing. US description for
APCR, also used to describe early APDS
hybrid a mechanism which uses more than one operating principle
igniter charge intermediate charge which magnifies the
primer burn, helping to burn the propellant
ignition the igniting of propellant by a primer
inert a cartridge or explosive which cannot fire or detonate
intermediate cartridge-a
cartridge which is intermediate in power between the pistol rounds use in an SMG
and full-power rifle/MG rounds
internal ballistics the science of the passage of a projectile
down a gun barrel
iron sights-metal
sights without an optical element, consisting of a rearsight close to the eye,
and a foresight near the muzzle
KwK Kampfwagenkanone (German): tank gun
Lafette (German): gun mounting
lands the smaller interior diameter of a rifled barrel;
between the grooves
lead computing gunsight a gunsight which calculates the
correct point of aim for deflection shooting
leaf sights rearsights
which consist of flat pieces of metal with a notch in the top for aiming.
Several flip-up 'leaves' of different heights may be provided to allow aiming at
different ranges
Leuchtspur (German): tracer; often written L'Spur
linear action a gun mechanism in which the elements reciprocate
in line with the gun barrel
link an element of an ammunition belt
linkless feed a method of supplying ammunition to a gun
in which the cartridges are not linked together
LMG light machine gun (can be carried by one man, usually fired from a
bipod)
lock time the period of time between pressing the trigger
or gun button and the first shot being fired
long recoil a type of gun operating mechanism
long-stroke piston a
type of gas operation in which the gas piston is attached to the bolt carrier
and drives it all the way to the back of the recoil stroke (see 'short-stroke
piston')
LSW light support weapon (squad LMG)
LV low velocity
machine gun an automatic weapon of less than 20mm calibre
magazine a container which holds ammunition ready for loading
into a gun
magazine follower the
moving part of the magazine, between the spring and the ammunition, which
transfers the spring pressure to the ammunition
manually operated a gun in which the firing cycle is operated
by a manual crank or lever
MBR main
battle rifle
MG machine gun (German: Maschinengewehr)
micro calibre a
rifle calibre smaller than the current 5.45 / 5.56mm
Minengeschoss or M-Geschoss (German): mine shell
mine shell a thin-walled, lightweight type of HE projectile
MK (German) Maschinenkanone: automatic cannon
MMG medium machine gun: a heavy gun of rifle calibre
moteur-canon (French) motor cannon: an aircraft cannon
designed for mounting between the cylinder banks of a vee-engine,
firing through a hollow propeller hub.
mounting the method of supporting a gun ready for firing
multiball a cartridge which contains several projectiles
(see duplex, triplex)
multipurpose ammunition ammunition with a mixture of capabilities
(AP, HE, I): associated with the Norwegian firm of Nammo Raufoss
muzzle the end of the barrel from which the projectile
emerges
muzzle blast the violent escape of gun gas from the muzzle
as a projectile leaves the barrel
muzzle booster a device fitted to the muzzle to use some
of the muzzle blast to increase recoil, to assist the action of
recoil-operated guns
muzzle brake a device fitted to the muzzle which deflects
part of the muzzle blast to the side or rear in order to reduce
recoil
muzzle energy a calculation of the energy of a projectile
as it leaves the muzzle; a function of projectile velocity and
weight
muzzle velocity the speed of a projectile as it leaves
the muzzle
NATO North Atlantic Treaty Organisation
neck the part of a cartridge case which holds the projectile
necked-down a cartridge case which has its neck reduced
in diameter to accept a smaller calibre projectile than the case
was designed for
necked-up (or necked-out) a cartridge case which has its
neck increased in diameter to accept a larger calibre projectile
than the case was designed for
obturation the sealing of a gun breech to prevent the
escape of gun gas on firing (in automatic weapons, normally achieved
by the cartridge case); also forward obturation achieved by the
driving bands
obus (French): shell
OCSW Objective Crew Served Weapon; US programme for a light
automatic 25mm support weapon. Now known as ACSW
OICW Objective Individual Combat Weapon; US programme for
a new infantry weapon combining 5.56mm and 20mm calibres
open bolt an automatic weapon designed to commence the
firing cycle without a cartridge loaded into the chamber (see
closed bolt)
optical sights sights
using glass lenses, which may be of unit magnification (i.e. non-magnifying) or
telescopic
optronics the combination of OPtical and elecTRONIC systems
to provide day/night/all-weather sights
ORO Operational
Research Office (US Army)
ounce (oz) UK and USA measure of weight; 1 oz = 28.35 grams.
over-bore a cartridge which has a case capacity too large
for all of the propellant to be efficiently utilised
PaK Panzerabwehrkanone (German): anti-tank gun
pan magazine a flat, circular magazine in which the cartridges
are held pointing inwards: see drum and helical drum
Panzergranat patrone (German): armour piercing cartridge
Panzerbrandsprenggranatpatrone L'spur m. Zerl (German):
armour piercing high-explosive incendiary cartridge with tracer
and self-destruct
Patrone (German): cartridge
PDW personal
defence weapon: a class of firearm midway between a pistol and a rifle, lighter
and firing smaller-calibre ammunition than an SMG
penetration the ability of an AP shot to penetrate armour
percussion ignition a method of igniting cartridges by
striking a percussion primer with a firing pin
PFHE pre-fragmented high explosive
Pfeilgeschoss (German) arrow shell: a long, fin-stabilised
HE projectile
Picatinny rail-an
American type of universal mounting rail, to which can be attached a wide range
of sights
and accessories
pintle mounting a type of flexible mounting in which the
gun is mounted at the top of a vertical rod
pistol grip the
grip for the firing hand, immediately behind the trigger
piston primer a special primer designed to be pushed out by gas pressure on firing, in order to operate the bolt unlocking mechanism
pivoting block a gun mechanism in which the breechblock
movement is pivoted
pom-pom unofficial name for a slow-firing automatic weapon,
usually of 37 or 40mm calibre
primary extraction the
act of a gun mechanism in pulling a fired case from the chamber
primer a percussion cap fitted into the head of a cartridge
case, used to ignite the propellant
primer pocket the part of a cartridge case into which the
primer fits
progressive rifling rifling which commences with a gentle
or zero twist, which gradually increases in twist down the length
of the barrel
projectile any bullet, shot or shell fired from a gun
propellant the chemical which burns rapidly to generate
gas which accelerates the projectile up the gun barrel
propeller disc the area swept by the blades of an aircraft
propeller
propeller hub or boss the central part of an aircraft propeller,
which may be made hollow to allow an engine-mounted gun to fire
through it
proximity fuze a shell fuze which is triggered by the close
proximity of a target
pyrophoric gives off sparks on impact and/or ignites spontaneously
at high temperature
Pzgr Panzergranate (German): AP Projectile
R rimmed cartridge case (when it occurs at the end of a
cartridge designation, as in 20x99R)
rail gun see electromagnetic gun
railway gun a gun mounted on a railway wagon
rate of fire frequency with which individual shots are
fired in an automatic weapon, usually measured in rpm
rebated rim a cartridge case with a rim of smaller diameter
than the case body
RB rebated rim (case description, added to the end of a
cartridge designation, also given as RR)
RCAR reduced-calibre
assault rifle: with a calibre smaller than the full-calibre 7.62 mm rounds
RCMG rifle calibre machine gun, typically of 7.5-8mm calibre
receiver the body of the gun, to which the barrel and operating
mechanism are attached
recoil operated a gun mechanism operated by the recoiling
gun barrel
reflector sight a gunsight in which the aiming marks are
reflected onto an angled glass plate through which the gunner
views the target
retarded blowback a
variation of the blowback mechanism in which, although the bolt is never locked
to the barrel, the initial movement of the bolt is resisted by a part of the
action, to give the bullet time to leave the muzzle. This is sometimes referred
to as delayed blowback (qv) although the principles are slightly different
reticle the markings visible in an optical sight which indicate where to aim, and sometimes the corrections needed for different ranges
revolver cannon a normally single-barrel gun with a rotating
cylinder containing several chambers, each of which is loaded
and unloaded in stages, and fired as it comes into line with the
barrel
rifle grenade a
grenade intended to be fired by a rifle; it fits onto the end of the barrel, and
may either trap the bullet or permit it to pass through, using only the energy
of the expanding gas to drive it (earlier models required a blank cartridge to
fire them)
rifling the spiral grooving within a gun barrel which grips
the projectile and spins it in order to ensure its stability (see
progressive rifling)
rifling twist the
angle of the rifling, normally expressed as the length of barrel required for
the rifling to turn the bullet through 360 degrees
rimfire a cartridge which is ignited by means of a percussion
compound contained within the rim (see centrefire)
rimless (case) a cartridge case in which the rim is the
same diameter as the case body, separated from it by an extractor
groove
rimmed (case) a cartridge case with a rim which has a larger
diameter than the case body
rotary cannon a multi-barrel gun with several parallel
barrels rotating around a common axis, each barrel being loaded
and fired in turn
rotary lock the locking of the bolt to the barrel extension
by a rotary movement
round (of ammunition ) a single cartridge (or equivalent)
rpg rounds per gun
RR rebated rim (also given as RB)
rpm rounds per minute; the usual measure of rate of fire
Rüstsatz, Rüstsätze field conversion set(s)
(German): not fitted at the factory
sabot a sleeve into which a sub-calibre projectile is fitted,
to enable it to be fired from a larger-calibre weapon: the sabot
breaks up and falls away after the projectile leaves the muzzle
SABR USA:
selectable assault battle rifle (alternative name for OICW)
saddle drum a type of drum magazine in which the cartridges
are held in two small connected drums on either side of the action,
from each of which rounds are fed in turn
salvo squeezebore a multiball system in which the projectiles
are of the squeezebore type
SAP(HE) semi-armour piercing (high explosive)
SAW squad
or section automatic weapon; another term for LMG
SAWS Small Arms Weapon Systems: 1960s US study
Schräge Musik jazz or oblique music (German): a type
of gun mounting used by night fighters, in which the barrels point
upwards and forwards
SCHV small-calibre
high-velocity: US project post-1945
SCR / SCAR USA: special forces combat (assault) rifle: 2000+ project to produce modular multi-purpose rifles for special forces
SD self destruct: an HE projectile which is designed a
detonate a few seconds after firing
SDR sectional density ratio; the ratio between calibre
and projectile weight: together with the projectile shape this
determines the ballistic coefficient
selective fire can fire semi or fully automatically
selector switch the
control switch on a gun by the which the user can select between semi or fully
automatic fire; it is usually combined with the safety catch and (on some
models) a burst fire mode
semi-automatic a rifle which automatically fires, ejects
and reloads each time the trigger is pulled: also used to describe
artillery in which the fired case is automatically ejected but
a new round is manually loaded
semi-rimmed (case) a cartridge case which has a rim only
slightly larger in diameter than the case body, separated from
it by an extractor groove: also known as semi-rimless
shaped charge see hollow charge
shell a projectile which is hollow in order to contain
HE or other contents
short recoil a type of recoil-operated gun mechanism
short-stroke piston a
type of gas operation in which the gas piston only moves back a short distance,
'kicking' the bolt carrier to the rear (see 'long-stroke piston')
shot any solid armour-piercing projectile (i.e. contains
no HE)
shoulder the part of a cartridge case where the diameter
reduces sharply from the case body to the neck
shrapnel a type of anti-personnel artillery ammunition
which consists of a shell containing metal balls in the forward
part and a small bursting charge at the rear, detonated by a time
fuze to explode just before reaching the target: named after its
19th century inventor (nowadays loosely used to describe shell
fragments)
sights the devices used to aim a gun
sight base the
distance between the front and rear sights; the longer this is, the more
accurately a weapon can be aimed
silencer muzzle attachment to eliminate flash and blast; more accurately known as a suppressor
single base a type of propellant
skeleton butt type
of buttstock which consists of an empty frame rather than solid wood or plastic.
Usually designed to fold
slant range line-of-sight range from an AA position to
a target aircraft
sliding block a type of gun action locking mechanism which
moves across the breech face
sling a
strap used to carry, and sometimes to steady, a rifle
small arms weapons intended to be carried by a soldier rather than fitted to a mounting
SMG sub-machine gun
smoothbored a barrel which is not rifled (used with fin
stabilised ammunition)
SOCOM USA:
special operations command
soft recoil see counter-recoil
SOPMOD USA:
special operations peculiar modifications programme
SPAAG self-propelled anti-aircraft gun: usually mounted
on an AFV chassis
spin stabilised a projectile whose flight is stabilised
by being rotated by rifling
SPIW USA:
special purpose individual weapon (1960s project)
SPR USA: special purpose rifle (5.56 mm sniper rifle)
Sprenggranate (German): HE shell
squeeze bore a gun in which special projectiles are fired
down a tapered barrel, or fitment to the end of the barrel, thereby
reducing their diameter
spire point A
bullet with a finely tapered nose for the optimum ballistic coefficient
SR semi-rimmed (or semi-rimless); a type of cartridge case
stabilised mounting a mounting in which the gun is kept
to a constant point of aim regardless of the movement of the vehicle
or ship which carries it
STANAG STANdardisation AGreement: applies to NATO equipment
Stellite a heat-resistant material used to line gun barrels
straight-cased cartridge a cartridge case which little
or no taper between the head and the neck; which therefore has
no shoulder
striker a long, spring-driven firing pin
striking angle the angle at which an AP projectile strikes
armour plate: two different conventions have applied; in one,
a strike perpendicular to the plate is called 0°, in NATO
it is called 90°
strip a number of cartridges linked rigidly together for
ease of loading
sub-calibre a projectile which is smaller than the bore
of the gun. For firing, it is supported by a sabot. See APDS,
APFSDS and full calibre
sub-calibre training a cartridge used for training purposes
in a much larger calibre (usually artillery) weapon via an adaptor
sub-machine gun a portable machine gun normally designed
to use pistol ammunition
sub-projectiles projectiles which are carried by a larger
projectile
suppressor muzzle
attachment to reduce flash and blast
SUU (American) Suspended Undercarriage Unit: used to designate aircraft gun pods
SV super velocity; implies a lighter than standard projectile
synchronised a gun mounting fitted to a piston-engined
fighter in which the gun is designed to fire through the propeller
disc: each shot has to be precisely timed (synchronised) to avoid
hitting a propeller blade
T tracer (when attached to a projectile designation)
taboo zone restriction on the freedom of movement of a
flexible gun mounting to prevent firing at own ship or aircraft
taper bore see squeeze bore
telescoped ammunition ammunition in which the projectile
is buried within the cartridge case
telescoping stock-a
buttstock which can be shortened to reduce its overall length
terminal ballistics the science concerning the performance
of projectiles on striking the target
time fuze a fuze fitted to an HE shell which detonates
it a predetermined time after firing
time of flight the time taken for a projectile to reach
its target
toggle joint a type of elbow joint used in some short-recoil
gun mechanisms
TP target practice: a type of projectile or cartridge used
for training
tracer a chemical compound in the base of a projectile
which burns slowly, giving a visible indication of its trajectory
trajectory the curve traced by a projectile in flight
traverse the movement of a gun in its mounting through
a horizontal arc
triple base a type of propellant
triplex loading a cartridge which contains three projectiles
(see duplex, multiball)
tripod a type of gun mounting used with light portable
weapons
Trommel (German): a drum magazine
tumble when
a bullet turns end-over-end, e.g. after striking the target
trunnion Projection from a gun body used to mount the gun;
traditionally at the point of balance
Übungsmunition (German): often written Üb; practice
ammunition
Vierling quadruple (German): a four-barrel gun mounting
VT WW2 code letters for a proximity fuze
Warsaw Pact-an
Eastern European military alliance, set up in opposition to NATO and dominated
by the USSR, which existed between the 1950s and the 1990s.
water-cooled a weapon which achieves barrel cooling by
means of a water jacket
Wolfram (German): tungsten
yaw when
a projectile fails to fly point-first, e.g. after striking something in flight;
taken to extreme, the projectile tumbles end-over-end (tumbles)
Zerleger (German): self-destroying (fuze), often written Zerl; m. Zerl means mit Zerl (with self-destruct), o. Zerl means ohne Zerl (without self-destruct)
Conversion Factors
The following approximate conversion factors will convert metric to Imperial measures:
To convert millimetres to inches divide by 25.4
To convert centimetres to inches divide by 2.54
To convert metres to feet multiply by 3.28
To convert metres to yards multiply by 1.1
To convert kilometres to miles divide by 1.61
To convert grams to grains multiply by 15.432
To convert grams to ounces divide by 28.35
To convert kilograms to pounds multiply by 2.2