Custom Search
  
COMPLETION/ENTRY OF LI
CENSES TO PURCHASE/ 
PISTOL SALES RECORDS 
N.C.I.C. CODES 
NCIC codes are required for manufacturers for en
try into the Automated Pistol Registration 
System (APRS).  
SIGNAT
URES 
Verify that all documents have the required sig
natures: chief of police, sheriff (or authorized 
deputies) the owner of the pistol on both the Lice
nse to Purchase and Pistol Sales Record and 
the notary’s signature on the License to Purchase 
.  
VERIFICATION OF GUN DESCRIPTION 
Verify that at a minimum the serial number, m
anufacturer, caliber and type are complete on the 
License to Purchase or Pistol Sales Record.  
PRODUCTION NUMBER
LISTED AS SERIAL NUMBERS FOR SW 
If the serial number does not appear to be correct, please attempt to contact the owner for 
verification.
1. Production numbers on Smith & Wesson are generally 4 or 5 digits and are found on the 
crane (hinge) of a revolver.  
2. The manufacturer's serial number is located on the BUTT of the weapon. (Remove grips 
that may cover the serial number.)  
3. If the correct serial number is 4 or 5 digits, indicate "butt #" on the License to Purchase or 
Pistol Sales Record so the Fi
rearms Records Unit will not a
ttempt to verify further.  
4. If the weapon is of antique vintage, the serial
number may be in a different location (usually 
on inside of butt strap directly behind trigger guard).  
OTHER INFORMATION TO LOOK FOR IN COMPLETION OF DOCUMENTS
1. 
Verify that street/city addresses include numbe
rs, street name, and city. Be sure that “Date 
of Birth” is completed correctly and does not reflect the current year.  
2. 
If a License to Purchase or Pistol Sales Records is issued
for a frame only, indicate the caliber 
that will be chambered and indicate "frame only" in Miscellaneous field.  
3. 
If caliber is unknown, indicate "0000" in the Caliber field.  
4
. 
.38-caliber S&W CTGE on barrel means pistol
takes a 38 Smith & Wesson cartridge. This 
may not be the manufa
cturer of the pistol.  
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FIREARMS TERMINOLOGY 
ACCESSORY BARRELS   
1.  Additional barrels that may be installed on 
a frame or receiver for the   purpose of 
altering the caliber, gauge or barrel length of a firearm. An accessory
barrel may have 
an attach
ed fore-end or other attachments.
2.  Any barrel that changes the caliber of a firearm, that is truly a barrel only and   does 
not have a breech mechanism of 
a kind or type normally associated with the parent 
firearm, is deemed to be an Accessory Barrel, 
whether or not it is attached to a barrel 
extension or “upper receiver.”  
AIR, SPRING OR GAS FIREARM   
A firearm design that uses compressed air, compressed gas or a spring to propel a projectile.  
AMMUNITION   
One or more loaded cartridges consisting of a primed cartridge case and propellant. May or may 
not contain one or more projectiles (Example
s: Ball Ammunition, Blank Ammunition and Duplex 
Ammunition).  
AMMUNITION, METALLIC  
A generic term for rim-fire and center-fire a
mmunition having a metallic cartridge case.  
AMMUNITION, CASELESS   
Ammunition that has the propellant charge molded to the base of the bullet or molded around the 
bullet, not enclosed in any kind of a cartridge case.  
AUXILIARY CHAMBER ADAPTERS   
A device that may be inserted into a firearm to adapt the original chamber to fire a different 
cartridge. This adapter may have a section of barrel attached.  
BALLISTICS   
The study of a projectile in motion.  
BALLISTICS, EXTERIOR   
The study of the motion of a projectile after it leaves the barrel of the firearm.  
BALLISTICS, INTERIOR   
The study of the motion of projectile(s) within t
he bore of a firearm from the moment of ignition 
until exit from the barrel.  
BALLISTICS, TERMINAL    
The study of the projectile’s impact effect on the target.  
BARREL, RINGED   
A barrel that has been fired while containing a bore
obstruction, without catastrophic failure. The 
resultant excessive radial pressure causes circumferential bulge in the barrel.  
BARREL TIME   
The elapsed time from the ignition of a cartridge and the bullet’s leaving the cartridge case neck 
to the time the bullet exits the barrel.  
BARRELLED ACTION   
A shotgun or rifle without the stock.  
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BARREL   
That portion of a firearm through which a project
ile or shot charge travels under the impetus of 
powder gasses, compressed air or other like means.
A barrel may be either smooth or rifled.  
BLOWBACK   
This system in its simplest form relies on the 
mass of the breech block and the strength of the 
return spring to accomplish the locking cycle in keeping with the law of physics dealing with 
inertia. The recoiling mass being much greater than the mass of the projectile, there is a time 
delay in the opening of the breech until the 
residual gas pressures have dropped to a sate 
operating level.  
BOLT ACTION   
A magazine-repeating firearm design in which the breech bolt or closure device operates in line 
with the bore. This type of action is manually operated by a permanently fixed projection or 
handle attached to the bolt or closure device, usually known as the bolt handle.  
BOLT/BREECH BOLT   
The locking and cartridge head support mechanism of a firearm that operates in line with the axis 
of the bore (Examples: Colt AR 15 rifle, Winchester Model 70).  
BOLT RELEASE   
A device that allows the bolt to be removed from the firearm.  
BOLT STOP    
A device that retains the bolt in 
the firearm during normal operation.  
BREECH BLOCK   
The locking and cartridge head support mechanism of a firearm that does not operate in line with 
the axis of the bore (Example: FN FAL rifle, Bren gun).  
BREECH LOADER  
Any firearm loaded with a cartridge or propellant from the rear of the bore.  
BREECH LOADING, SINGLE BARREL-SINGLE SHOT OR MULTIPLE BARREL-MULTIPLE 
SHOT FIREARMS   
Firearms in which the action of loading is acco
mplished one cartridge at a time in each barrel, 
usually by hand. The breech is then manually clos
ed, a shot or shots are fired, the breech is 
opened manually, and the loading action is repeated by hand for each barrel to be discharged. 
BREECH PLUG   
In percussion and flint-lock firearms, the metal par
t that is threaded into the breech end of the 
barrel and usually incorp
orates the top tang.  
BREECH, STANDING   
That portion of the receiver or frame of a revolver
or break-open single-shot or multi-barrel firearm 
that supports the head of the cartridge when it is fired.  
BULLET, DUMDUM   
An obsolete term referring to a bullet with an exposed lead tip for the purpose of expansion upon 
entering a medium with greater density than air. 
Manufactured at the British Arsenal located at 
Dumdum, India.  
BULLET, INCENDIARY   
A bullet containing a chemical compound that ignites on impact to start fires.  
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REPEATING FIREARM                       
A firearm with a mechanism for feeding ammunition into the chamber known as magazine  
or belt that accomplishes the entire cycle of
operation, either manually or externally  
powered, or by utilizing some of 
the power genera
ted by the propellant 
gas or recoil force.  
Some of these mechanisms, externally pow
ered systems or hand operated systems of  
operation, include:  
1.  Pump action mechanisms  
2.  Lever action mechanisms  
3.  Bolt action mechanisms  
4.  Auto-loading or semiautomatic mechanisms; recoil-operated (both long and short 
recoil) and gas-operated mechanisms  
5.  Automatic mechanisms; recoil operated (both long and short recoil) and gas operated  
6.  Manually powered, hand-operated, ro
tary-barrel mechanisms (Gatling gun)  
7.  Externally powered mechanisms (V
ulcan Gatling or Hughes Chain gun)  
REPRODUCTION       
The modern manufacture of any firearm that ha
s ceased to have patent protection and is usually 
no  longer  manufactured  by  the  original  maker.  No
rmally  the  reproduction  is  equal  to  or  better  in  
quality  of  material  and  workmanship  than  the  original  and  in  some  cases  may  be  an  exact  
duplicate with interchangeable parts and components.  
REVOLVER                                      
A firearm, usually a handgun, with a cylinder having several chambers so arranged as to rotate around 
an ax
is and be discharged successively by the same
firing mechanism  
RIFLING                                   
A system of helical grooves cut into the bore of a firearm barrel. The purpose of rifling is to impart 
spin to a projectile passing thro
ugh the barrel, thus giving the pr
ojectile gyroscopic stability during 
its flight to the target.  
RECEIVER                                
The receiver, which is also known as the frame, 
is the basic component of a firearm to which all 
other components are assembled or attached. In mo
st firearm designs the barrel is assembled to 
the receiver and the receiver houses the breech mechanism, trigger and firing mechanisms.  
RIFLE                                                                       
A firearm designed or redesigned, made or
remade, and intended to be fired from the shoulder and 
designed or redesigned and made or remade to use the energy of the explosive in 
a fixed metallic 
cartridge to fire only a single projectile through a rifled bore for each single pull of the trigger.  
SAFETY CATCH             
Any type of applied safety catch. A mechanical 
device that enables the sh
ooter to lock the firing 
mechanism of a firearm voluntarily. Also called a manual safety or manually operated safety 
catch. (NOTE: On most firearms with a fully-automatic fire capability, the fire selector usually 
incorporates the safety catch.  
SAFETY PRECAUTIONS                         
A series of actions, verifications and precautions that must be undertaken before, during and after handling
a firearm o
r during firing of firearms to prevent accidents and personal injury.  
SAFETY, MECHANICAL                     
An  automatic  device  that  prevents  firing  a  firearm  as  long  as  certain  conditions  are  not  met.  A  
feature  incorporated  into  the  firearm's  design  
to  ensure  that  the  weapon  cannot  fire,  howeve
r 
mishandled,  before  the  breech  is  properly  locked;  and  that  the  breech  will  not  unlock  until  such  
time  as  the  projectile  has  left  the  barrel  and  
pressures  generated  to  expel  the  projectile  have  
ropped to a safe operating level.  
d
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SEAR                                     
Part of the firing mechanism, linked to the trigger, that retains the hammer or striker in the cocked 
position until the trigger is pulled.  
SELECTOR                                
1. In double-barreled firearms, a device to a
llow the shooter to choose which barrel is 
to   be fired by the first pull of the trigger.  
2. A lever that enables the shooter to choos
e the type of fire (full-automatic/semi-  
automatic) or apply the safety catch; in t
he case of some automatic weapons, the  
selector enables the shooter to choose high or low cyclic rate of fire.  
SEMIAUTOMATIC                          
A repeating firearm requiring a separate press of 
the trigger for each shot 
fired, using the energy 
of  discharge  to  perform  a  portion  of  the  operating  cycle.  Semiautomatic  actions  are  sometimes  
referred to as auto-loading or self-loading actions.  
SERIAL NUMBER                         
A  combination  of  numbers  and  letters  applied  to  a  
firearm  in  order  to  uniquely  identify  it  from  all  
others of its type. There is a requi
rement for the serial number to contain a minimum of one digit in 
the combination of letters and numbers that comprise the serial number.  
SHOT COLLAR                             
Plastic or paper insert surrounding the shot charge in
a shot shell to reduce distortion of the shot 
when passing through the barrel.  
SHOTGUN                              
A  firearm  designed  or  redesigned,  made  or  remade  and  intended  to  fire  from  the  shoulder  and  
designed or redesigned and made or remade to use 
the energy of the explosive in a fixed shotgun 
shell to fire through a smooth bore either a number of
ball shot or a single projectile for each single 
function of the trigger.  
SHOT                                 
Pellets of various sizes used in shot shells and shot cartridges.  
SIGHT, BUCKHORN                       
A rear sight for rifles that has the “V” notch at
the bottom of an almost completely closed V.  
SIGHT, PAINE                               
A  rear  sight  on  pistols  or  revolvers  having  a  flat  top  with  a  V-shaped  notch  used  with  a  bead  
pped front sight. Named after Ira Paine, a 19
th
-century exhibition and competition shooter.  
to
SIGHT, PATRIDGE                           
A rear sight on pistols or revolvers having a flat top with a square notch used with a broad 
flat-topped front sight. Named after E.E. Patridge.  
SIGHT, PYRAMID                            
A type of front sight of triangular appe
arance. Also called a Barley-Corn sight.  
SIGHT RADIUS                             
The distance between the rear sight and the front sight on a firearm.  
SIGHT RAMP                            
A front sight mounted on a ramp base.  
SIGHT TANG                               
Any sight mounted on the upper tang of a firearm.  
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5
SIGHT TANGENT                          
A rear sight in which the blade is adjusted for el
evation correc
tion 
by sliding along a curved cam o
r 
cams. The term is also us
ed for vertically standing back sights with sliding rear apertures.  
SIGHTS                                      
1. ADJUSTABLE - Usually taken to mean a rear sight that is adjustable for windage 
or   elevation or both. O
ccasionally adjus
table front sights may be found on pistols or 
revolvers.   
2. APERTURE - A form of metallic sight, fr
ont or rear, containing an aperture or disc 
with   a hole. Also called a Peep Sight.  
3. BEAD  - A form of front sight, usua
lly found on shotguns, 
having the appearance 
of   a round bead.  
4. EXPRESS- A series of rear sights, mounted on one base, with folding sight 
leaves   to be used for varying ranges or elevations.  
5. FIXED - Metallic sights that are not adjustable.  
6. GLOBE - A form of front sight usually used 
on target rifles, generally cylindrical in shape 
and often arranged to accept various insert
s containing either rings or posts.  
7. HOODED - A front sight that is provided with a cover to shade it from direct light.  
8. TELESCOPIC - A sight containing optical elements that magnify the target.  
9. VERNIER - A long-range sight with a 
mechanism for adjusting windage, elevation 
or  both, as read on a scale in conjunct
ion with graduations on a longer, linear 
calibrated  scale.  
SILENCER                                
A device capable of attachment to the barrel of 
a firearm designed or intended to reduce the 
noise of discharge of ammunition  
SINGLE-SHOT                           
A single-barrel firearm design that must be manually loaded, having no internal or external 
magazine feed device. Certain single-shot firearms
are operated by levers and certain single-shot 
firearms are operated by a bolt. Regardless of 
the method of operating the breech mechanism, 
these firearms are single-shot firearm actions.  
SINGLE ACTION                            
An action that requires the manual cocking of the 
hammer before pressure on the trigger releases 
the firing mechanism.  
SMALL ARMS                  
Hand-operated, hand- or shoulder-controlled firearms, including machine
guns, up to and including 
.50 caliber. It is generally ac
cepted that firearms in excess of .50 caliber up to and including 30mm 
caliber are called cannon, while firearms in excess of 30mm are artillery.  
SPRING                                  
A mechanical device used to store energy.  
STOCK                                
A component, usually wood, to which a barreled ac
tion is attached, enabling the shooter to hold 
the firearm and control it from the shoulder.  
SUBMACHINE GUN                         
A firearm design that, as originally designed an
d manufactured, has the capacity of firing 
projectiles in rapid succession during one press of
the trigger, whether or not it has been altered 
to fire only one projectile with one such press. In general terms a submachine gun is a compact, 
hort-barreled, air-cooled, magazine-fed firearm,
usually chambered for a pistol cartridge.  
s
SYMPATHETIC DISCHARGE                 
The simultaneous firing of two or more cartridges 
chambered in the cylinder of a revolver, only one 
of which is in exact alignment with the barrel; 
normally associated with percussion revolvers.  
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TAKE-DOWN FIREARMS                    
A rifle or shotgun in which the barrel and sometimes the magazine and fore-end are designed to 
be removed from the receiver readily, without the use of tools, for the purpose of making a more 
compact  item  for  ease  of  transportation.  When  
additional  barrels  are  available  for  a  take-down  
firearm, these barrels are considered accessory 
barrels. See definition of accessory barrels.  
TOP-BREAK                              
A term used to describe a single-shot, multi-barrel
or revolver mechanism on which the barrel o
r
barrels  are  allowed  to  tip  down  at  the  muzzle
exposing  the  chamber  or  chambers  for  loading,  
unloading or extraction of cartridges.  
TOP-LEVER                                 
The lever located on the top of the breech end of
hinged-frame firearms that when pushed to one 
side will unlock the barrel
(s) from the receiver or 
frame and allow them to move (left, right, forward, 
rearward, tip-down or tip-up).  
TRIGGER                                 
That part of a firearm mechanism that is moved 
manually to cause the firearm to discharge.  
TRIGGER , RELEASE                       
An unconventional mechanism in which the firearm is
fired by the release, rather than by the pull 
of the trigger.  
TRIGGER, SET                              
Either a single or double trigger arrangement 
on which the required trigger pull force can be made 
very light by means of a "setting" mechanism.  
UNLOCKING                               
A stage in the cycle of operation of a firearm in which the bolt, breech block or standing breech is 
removed from fixed relationship with the chamber, so
as to permit the extraction and ejection cycle 
to take place after pressures have dropped to a safe operating level.  
VIERLING                                    
A four-barreled shoulder arm that usually 
has two smooth-bored and two rifled barrels.  
WATER TABLE                             
The flat portion of the receiver or frame on fir
earms that break open, ex
tending forward from, and 
is  approximately  at  right  angles  to,  the  standing-b
reech  face.  This  is  the  surface  on  which  the  
barrel flats rest when the action is closed.  
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A bullet containing a primer or other explosive designed to explode on impact.  
CALIBER   
1.  Firearms--the approximate diam
eter of the circle formed by the tops of the lands of a  
rifled barrel.  
2.  Ammunition--a numerical term, without the decimal point, included in a cartridge  name  
to indicate the approximate bullet diameter.  
CAPE RIFLE/CAPE GUN   
A double-barreled shoulder arm with barrels side by side, one being smooth bore and the other 
being rifled.  
CAP, PERCUSSION   
A
small, generally cylindrical metallic cup cont
aining a primary explosive used to ignite the 
powder charge in muzzle-loading (and some breech-loading) firearms.  
CARBINE   
A rifle of short length and light weight or
iginally designed for mounted troops.  
CARTRIDGE CASE   
The container for all other components that comprise a cartridge.   
CARTRIDGE, DUMMY   
An inert cartridge that cannot be fired.  
CHOKE   
An interior constriction at or near the muzzle 
end of a shotgun barrel bore for the purpose of 
controlling shot dispersion.  
CLIP/ CHARGER CLIP/ STRIPPER CLIP -  
A separate cartridge container/device to hold cartri
dges for the purpose of rapid reloading. In the 
case of certain firearms the charger clip becom
es an integral part at the firearm mechanism 
(Example: U.S. Rifle M-1 Garand). The term “clip” is also used erroneously to describe cartridge 
magazines.  
COCKING   
A stage in the cycle of operation of a firearm in 
which the firing mechanism is placed under spring 
tension.  
COMBINATION GUN   
A firearm having more than one barrel installed on the receiver in which the barrels are 
permanently attached to each other. In the case where there are two barrels, each barrel must be 
chambered for a different caliber cartridge. In the case of a Combination Gun having more than 
two barrels, the individual barrels of the firearm w
ill be chambered for at least two different caliber 
cartridges. This firearm may be found with two, three or even four barrels in any combination of 
rifle or shotgun gauges or calibers.  
COMMERCIAL VERSION   
A firearm design that is a semiautomatic version 
of a traditional military and police full-automatic 
firearm. Commercial version type code CV describ
es a firearm that, as it left the manufacturer, 
was designed and intended to fire semiautomati
c only. The type code CV describes only those 
firearms that would otherwise be unclassifiable 
by TYPE according to the existing system when 
the full-automatic capability is removed during manufacture.  
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8
COMPENSATOR   
A device attached to or integral with the muzzle
end of the barrel to utilize propelling gasses for 
counter recoil. Also called a muzzle brake.  
CONVERSION UNIT   
Any device that changes the caliber of the parent firearm, consisting of an assembly of parts; as a 
minimum comprised of a barrel and a breech me
chanism of a kind or type normally associated 
with the parent firearm and having a breech fa
ce capable of supporting the cartridge head.  
CONVERTED-AUTOMATIC   
A firearm that, as originally designed and manufac
tured, had the capacity of firing projectiles in 
rapid succession during one pressure of the trigger and has subsequently been altered to fire 
only one projectile with one such pressure.   
COOK-OFF   
The ignition of a cartridge by overheating.  
COPY  
A firearm manufactured in visual imitation of another firearm with or without the benefit of 
permission or license. These copies are normally
manufactured to gain an advantage in sales, 
marketing, or research and development costs at the expense of the company whose firearm is 
being copied. Copies are not normally dimensionally interchangeable with the firearm being 
copied. Also known as a counterfeit copy or knock-off.  
CONVERTIBLE   
The term convertible is applied to revolvers in which the cylinder may be interchanged with other 
cylinders to permit the firearm to discharge ca
rtridges of different calibers with the same 
approximate bullet diameter. When this concept is applied to firearms other than revolvers, for 
correct terminology refer to ”Auxiliary Chamber 
Adapters,” “Accessory Barrels” and “Conversion 
Units.”  
DAMASCUS   
An obsolete barrel-making process. The barrel is 
formed by twisting or braiding together steel and 
iron wires or bars. The resulting cable is then 
wound around a mandrel and forged into a barrel 
tube. Sometimes called a “laminated barrel.”  
DEFLAG   
To burn with great heat and light, producing large 
volumes of gas. Smokeless gun powder is said 
to deflagrate.  
DERRINGER   
A generic term applied to a large variety of pocket-size pistols of any ignition system, single or 
multiple barreled. Sometimes spelled Deringer.  
DETONATION   
Exothermic reaction of a high ex
plosive; an extremely violent reaction at supersonic speed.  
DOUBLE ACTION   
A handgun mechanism in which a single pull of the trigger cocks and releases the hammer or 
striker.  
DRILL ROUND   
A
dummy cartridge supplied by the military for troo
ps to practice loading and unloading drills with 
firearms. See also Cartridge, Dummy.  
39
DRILLING  
A three-barreled shoulder arm in which a combination of smooth-bored and rifled barrels are 
used.   
DRY FIRING   
Firing of an unloaded firearm to practice firearm handling and shooting skills.  
EJECTION   
A stage in the cycle of operation of a firearm in 
which a cartridge or fired cartridge case is 
expelled from the breech of a firearm.  
EJECTOR   
A portion of the firearm mechanism that ejects or
expels cartridges or fired cartridge cases when 
the action is opened.  
EXTRACTION   
A stage in the cycle of operation of a firearm in 
which a cartridge or fired cartridge case is 
withdrawn from the chamber of a firearm.  
EXTRACTOR   
A mechanism for withdrawing the cartridge or fired 
cartridge case from the chamber of a firearm.  
FEEDING   
A stage in the cycle of operation of a firearm in 
which a fresh cartridge is introduced into the 
mechanism from an ammunition supply in such a way that the breech mechanism may insert the 
cartridge into the chamber. Feeding may also be accomplished manually.  
FIREARM   
A weapon from which a dangerous projectile may be pr
opelled by an explosive, or by gas or air.  
Firearm does not include a smooth bore rifle or handgun designed and manufactured exclusively 
for propelling by a spring, or by gas or air, BB’s not exceeding .177 caliber.  
FIRING   
A stage in the cycle of operation wherein the fi
ring mechanism is released by the sear and the 
primer of the cartridge is struck by the firing pin to fire a shot.  
FIRING PIN   
That part of a firing mechanism that strikes the pr
imer of a cartridge to initiate ignition of the 
propellant charge.   
FLECHETTE   
A thin, sub-caliber, fin-stabilized small dart or
arrow encased in a discarding sabot and loaded 
into small arms ammunition or a shotgun shell.   
FLINT-LOCK    
1.  Lock Mechanism--firing mechanism of a muzzle-loaded firearm wherein the frizzen is  
integral with a hinged pan cover. The strike of
the flint on the frizze
n produces sparks and  
simultaneously pivots the pan cover to expose 
the fine-grain black powder priming  charge 
contained in the pan.   
2. Firearm--muzzle-loading firearm utilizing 
a flint-lock ignition mechanism. There have  
been breech-loading, flint-lock firearms (Example: Ferguson rifle).  
FRIZZEN 
In flint-lock mechanism, the steel part placed
over the pan against which the flint strikes, 
producing the sparks necessary to ignite the black powder priming charge.  
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FULL-AUTOMATIC  
A firearm with the capacity to fire projectiles in
rapid succession during one press of the trigger.  
GAS OPERATION   
Method of operation of semiautomatic and automatic 
firearms in which the force derived from the 
propellant gases generated upon firing a cartridge is utilized to complete the cycle of operations. 
Gas operated firearms usually depend on springs 
to store energy for the purpose of feeding, 
loading, cocking and locking the mechanism.  
GRIP SAFETY   
A mechanical safety in the grip of some firear
ms that prevents firing unt
il it is depressed by the 
firing hand; this engages automatically when releas
ed to prevent the firearm from discharging. 
HANDGUN   
Any firearm designed, altered or intended to be aimed and fired by the action of one hand.  
HANG-FIRE   
An ammunition malfunction in which the cartridge ignition takes place after an appreciable delay 
(fraction of a second to several seconds) after the primer has been struck.  
HEADSPACE   
The distance from the closed breech face of the 
firearm mechanism to the surface in the chamber 
upon which the cartridge case bores.  
HEADSPACE GAUGE   
A mechanical device for measuring the distance fr
om the breech face of a firearm mechanism to 
that portion of the chamber against which a cartridge will bear. Headspace gauges are available 
in three types: minimum, maximum, and field gauges.   
HEADSPACE GAUGE – PURPOSE AND USE   
The purpose of measuring headspace is to insure
that the firearm mechanism will lock correctly 
when a maximum tolerance cartridge is loaded into a minimum tolerance firearm chamber 
(Minimum Headspace) and that the firearm is safe to fire a minimum tolerance cartridge in a 
maximum tolerance firearm chamber (Maximum 
Headspace) without the possibility of damage to 
the firearm or injury to the shooter or close spectators. Headspace gauges are used to decide 
whether to permit a firearm with headspace in exce
ss of the maximum tolerance to continue to be 
used in military service for emergency requirem
ents, and those with headspace in excess of the 
field requirement considered too dangerous for 
emergency use. Field headspace gauges have no 
legitimate civilian or commercial application.  
HEADSTAMP   
Numbers, letters and symbols stamped on the head 
of a cartridge case during manufacture to 
identify the manufacturer, caliber or gauge, date of manufacture or other information.  
IMPORTER   
The name of an individual or company that brings 
goods from off shore to the United States of 
America or Canada for resale or distribution.  
LEADS   
That area forward of the chamber of a firearm that
is groove diameter or slightly larger, extending 
forward to the origin or commencement of rifling. Also known as the Leed, Lead, Throat, 
Chamber Throat or Forcing Cone.  
LEVER ACTION   
A magazine-repeating firearm design wherein the 
breech mechanism is cycled by an external 
lever, generally below the receiver or frame.  
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1
LOADING   
A stage in the cycle of operation of a firearm in 
which the cartridge is fully inserted into the 
chamber in preparation fo
r the locking cycle.  
LOCKING   
A stage in the cycle of operation of a firearm in which the bolt, breech block or standing breech is 
solidly secure
d in a fixed relationship with the 
chamber, so as to resist being blown open by the 
pressures generated by firing.  
MANUFACTURER    
The manufacturer is the individual or company that manufactures or subcontracts the 
manufacture of any or all component parts of a 
firearm. It may be possible to identify the fully 
assembled firearm to the manufacturer if the 
firearm has been marked with the manufacturer’s 
company name or trademark.  
MANUFACTURE DATES                     
Where the date of manufacture is found mark
ed on a firearm of government contract or 
government arsenal production, the date of manuf
acture shall be included with the model, when 
necessary, to uniquely identify that particula
r firearm from all others of its type.  
MAKE
The make is normally the company name, abbreviation of the company name, brand or trade name 
associated with the particular firearm.  
MAGAZINE
1.  A container for cartridges that has a spring and a follower to feed those cartridges into  
the 
chamber of a firearm. The magazine may be detachable or an integral part of the  firearm.   
2.  A storage place for gun powder, ammunition or explosives.  
MACHI
NE GUN 
A firearm, as originally designed and manufactured, with the capacity of firing projectiles in rapid 
succession 
during one press of the trigger, whether or not it has been altered to fire only one projectile
with one such press.  
MAGAZINE-REPEATING 
FIREARM                  
A firearm fed by an inter
nal or external magazine. 
MAGAZINE SAFETY    
A mechanical safety mechanism found on some semiautomatic pistols that prevents firing when
the magazine is removed from the firearm.  
MIS-FIRE      
An ammunition malfunction in which firearm fails to discharge after the firing pin has struck an 
adequate 
blow to the primer and the initiated primer fails to ignite the propellant powder.  
MULTI-BARREL                                                                                                                    
A
multiple-barrel firearm designed with the barrels permanently attached to each other and 
capable of discharging multiple shots, 
contingent on the number of barrels.  
MUZZLE                                                
The end of the barrel from which the projectile emerges. 
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MUZZLE, CROWN                                         
Any of the various forms of muzzle treatment designed/meant primarily to protect the rifling. 
It may take the form of a counter-bore, radius or chamfering of the muzzle.  
MUZZLE BLAST                                                        
The resultant over-pressure blast /noise that occu
rs at the muzzle of a firearm when the projectile 
exits the barrel and the rapidly expanding 
propellant gasses are released.  
MUZZLE-LOADER                         
Any firearm that is loaded with gun powder and pr
ojectile(s) through the muzzle end of the bore.  
OPERATION CYCLE, FIREARM                                                                                                       
A series of mechanical or manually operated event
s that take place in all firearms during the 
discharge of ammunition. These terms are used to describe with technical accuracy the manner in 
which the mechanism functions. This series
of events is described as follows:    
1.   Cocking  
2.   Feeding  
3.   Loading  
4.   Locking  
5.   Firing  
6.   Unlocking  
7.   Extraction  
8.   Ejection  
(NOTE: These events do not necessarily 
occur in the order described above.)  
ORIGINAL                                                  
The word “original” refers to a model of firearm as produced by the manufacturer who first introduced
that model for commercial or contract sale
and also implies that a different business entity 
has copied 
or reproduced this model at some point in time.  
PARADOX GUN                                              
A firearm having a barrel design in which the majo
r 
length of the barrel is smooth and the la
st 10 to 12
centimeters are rifled.  
PERCUSSION       
A means of ignition of a propellant charge by a mechanical blow against a primer or percussion cap.  
PISTOL  
A
loaded or unloaded firearm that is 30 inches or less in length, or a loaded or unloaded firearm 
that by its construction and appearance conceals it as a firearm.                                                
PROPELLANT                                    
As it refers to firearms or firearms ammunition, a chemical, low-explosive mixture or composition 
that 
when ignited burns rapidly (deflagrates), generating large volumes of gas (to propel a projectile).  
PUMP ACTI
ON                                
A magazine-repeating firearm design that is manually actuated in motion usually parallel to the barrel.
Pump Action firearms are also sometimes referred to as slide action or trombone action.  
RECOIL OPERATION                       
Method  of  operation  of  semiautomatic  and  automatic  firearms  in  which  recoil  energy  imparted  to  
the barrel is used to actuate the mechanis
m to complete the cycle of operations.  
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REPEATING FIREARM                       
A firearm with a mechanism for feeding ammunition into the chamber known as magazine  
or belt that accomplishes the entire cycle of
operation, either manually or externally  
powered, or by utilizing some of 
the power genera
ted by the propellant 
gas or recoil force.  
Some of these mechanisms, externally pow
ered systems or hand operated systems of  
operation, include:  
1.  Pump action mechanisms  
2.  Lever action mechanisms  
3.  Bolt action mechanisms  
4.  Auto-loading or semiautomatic mechanisms; recoil-operated (both long and short 
recoil) and gas-operated mechanisms  
5.  Automatic mechanisms; recoil operated (both long and short recoil) and gas operated  
6.  Manually powered, hand-operated, ro
tary-barrel mechanisms (Gatling gun)  
7.  Externally powered mechanisms (V
ulcan Gatling or Hughes Chain gun)  
REPRODUCTION       
The modern manufacture of any firearm that ha
s ceased to have patent protection and is usually 
no  longer  manufactured  by  the  original  maker.  No
rmally  the  reproduction  is  equal  to  or  better  in  
quality  of  material  and  workmanship  than  the  original  and  in  some  cases  may  be  an  exact  
duplicate with interchangeable parts and components.  
REVOLVER                                      
A firearm, usually a handgun, with a cylinder having several chambers so arranged as to rotate around 
an ax
is and be discharged successively by the same
firing mechanism  
RIFLING                                   
A system of helical grooves cut into the bore of a firearm barrel. The purpose of rifling is to impart 
spin to a projectile passing thro
ugh the barrel, thus giving the pr
ojectile gyroscopic stability during 
its flight to the target.  
RECEIVER                                
The receiver, which is also known as the frame, 
is the basic component of a firearm to which all 
other components are assembled or attached. In mo
st firearm designs the barrel is assembled to 
the receiver and the receiver houses the breech mechanism, trigger and firing mechanisms.  
RIFLE                                                                       
A firearm designed or redesigned, made or
remade, and intended to be fired from the shoulder and 
designed or redesigned and made or remade to use the energy of the explosive in 
a fixed metallic 
cartridge to fire only a single projectile through a rifled bore for each single pull of the trigger.  
SAFETY CATCH             
Any type of applied safety catch. A mechanical 
device that enables the sh
ooter to lock the firing 
mechanism of a firearm voluntarily. Also called a manual safety or manually operated safety 
catch. (NOTE: On most firearms with a fully-automatic fire capability, the fire selector usually 
incorporates the safety catch.  
SAFETY PRECAUTIONS                         
A series of actions, verifications and precautions that must be undertaken before, during and after handling
a firearm o
r during firing of firearms to prevent accidents and personal injury.  
SAFETY, MECHANICAL                     
An  automatic  device  that  prevents  firing  a  firearm  as  long  as  certain  conditions  are  not  met.  A  
feature  incorporated  into  the  firearm's  design  
to  ensure  that  the  weapon  cannot  fire,  howeve
r 
mishandled,  before  the  breech  is  properly  locked;  and  that  the  breech  will  not  unlock  until  such  
time  as  the  projectile  has  left  the  barrel  and  
pressures  generated  to  expel  the  projectile  have  
ropped to a safe operating level.  
d
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SEAR                                     
Part of the firing mechanism, linked to the trigger, that retains the hammer or striker in the cocked 
position until the trigger is pulled.  
SELECTOR                                
1. In double-barreled firearms, a device to a
llow the shooter to choose which barrel is 
to   be fired by the first pull of the trigger.  
2. A lever that enables the shooter to choos
e the type of fire (full-automatic/semi-  
automatic) or apply the safety catch; in t
he case of some automatic weapons, the  
selector enables the shooter to choose high or low cyclic rate of fire.  
SEMIAUTOMATIC                          
A repeating firearm requiring a separate press of 
the trigger for each shot 
fired, using the energy 
of  discharge  to  perform  a  portion  of  the  operating  cycle.  Semiautomatic  actions  are  sometimes  
referred to as auto-loading or self-loading actions.  
SERIAL NUMBER                         
A  combination  of  numbers  and  letters  applied  to  a  
firearm  in  order  to  uniquely  identify  it  from  all  
others of its type. There is a requi
rement for the serial number to contain a minimum of one digit in 
the combination of letters and numbers that comprise the serial number.  
SHOT COLLAR                             
Plastic or paper insert surrounding the shot charge in
a shot shell to reduce distortion of the shot 
when passing through the barrel.  
SHOTGUN                              
A  firearm  designed  or  redesigned,  made  or  remade  and  intended  to  fire  from  the  shoulder  and  
designed or redesigned and made or remade to use 
the energy of the explosive in a fixed shotgun 
shell to fire through a smooth bore either a number of
ball shot or a single projectile for each single 
function of the trigger.  
SHOT                                 
Pellets of various sizes used in shot shells and shot cartridges.  
SIGHT, BUCKHORN                       
A rear sight for rifles that has the “V” notch at
the bottom of an almost completely closed V.  
SIGHT, PAINE                               
A  rear  sight  on  pistols  or  revolvers  having  a  flat  top  with  a  V-shaped  notch  used  with  a  bead  
pped front sight. Named after Ira Paine, a 19
th
-century exhibition and competition shooter.  
to
SIGHT, PATRIDGE                           
A rear sight on pistols or revolvers having a flat top with a square notch used with a broad 
flat-topped front sight. Named after E.E. Patridge.  
SIGHT, PYRAMID                            
A type of front sight of triangular appe
arance. Also called a Barley-Corn sight.  
SIGHT RADIUS                             
The distance between the rear sight and the front sight on a firearm.  
SIGHT RAMP                            
A front sight mounted on a ramp base.  
SIGHT TANG                               
Any sight mounted on the upper tang of a firearm.  
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5
SIGHT TANGENT                          
A rear sight in which the blade is adjusted for el
evation correc
tion 
by sliding along a curved cam o
r 
cams. The term is also us
ed for vertically standing back sights with sliding rear apertures.  
SIGHTS                                      
1. ADJUSTABLE - Usually taken to mean a rear sight that is adjustable for windage 
or   elevation or both. O
ccasionally adjus
table front sights may be found on pistols or 
revolvers.   
2. APERTURE - A form of metallic sight, fr
ont or rear, containing an aperture or disc 
with   a hole. Also called a Peep Sight.  
3. BEAD  - A form of front sight, usua
lly found on shotguns, 
having the appearance 
of   a round bead.  
4. EXPRESS- A series of rear sights, mounted on one base, with folding sight 
leaves   to be used for varying ranges or elevations.  
5. FIXED - Metallic sights that are not adjustable.  
6. GLOBE - A form of front sight usually used 
on target rifles, generally cylindrical in shape 
and often arranged to accept various insert
s containing either rings or posts.  
7. HOODED - A front sight that is provided with a cover to shade it from direct light.  
8. TELESCOPIC - A sight containing optical elements that magnify the target.  
9. VERNIER - A long-range sight with a 
mechanism for adjusting windage, elevation 
or  both, as read on a scale in conjunct
ion with graduations on a longer, linear 
calibrated  scale.  
SILENCER                                
A device capable of attachment to the barrel of 
a firearm designed or intended to reduce the 
noise of discharge of ammunition  
SINGLE-SHOT                           
A single-barrel firearm design that must be manually loaded, having no internal or external 
magazine feed device. Certain single-shot firearms
are operated by levers and certain single-shot 
firearms are operated by a bolt. Regardless of 
the method of operating the breech mechanism, 
these firearms are single-shot firearm actions.  
SINGLE ACTION                            
An action that requires the manual cocking of the 
hammer before pressure on the trigger releases 
the firing mechanism.  
SMALL ARMS                  
Hand-operated, hand- or shoulder-controlled firearms, including machine
guns, up to and including 
.50 caliber. It is generally ac
cepted that firearms in excess of .50 caliber up to and including 30mm 
caliber are called cannon, while firearms in excess of 30mm are artillery.  
SPRING                                  
A mechanical device used to store energy.  
STOCK                                
A component, usually wood, to which a barreled ac
tion is attached, enabling the shooter to hold 
the firearm and control it from the shoulder.  
SUBMACHINE GUN                         
A firearm design that, as originally designed an
d manufactured, has the capacity of firing 
projectiles in rapid succession during one press of
the trigger, whether or not it has been altered 
to fire only one projectile with one such press. In general terms a submachine gun is a compact, 
hort-barreled, air-cooled, magazine-fed firearm,
usually chambered for a pistol cartridge.  
s
SYMPATHETIC DISCHARGE                 
The simultaneous firing of two or more cartridges 
chambered in the cylinder of a revolver, only one 
of which is in exact alignment with the barrel; 
normally associated with percussion revolvers.  
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TAKE-DOWN FIREARMS                    
A rifle or shotgun in which the barrel and sometimes the magazine and fore-end are designed to 
be removed from the receiver readily, without the use of tools, for the purpose of making a more 
compact  item  for  ease  of  transportation.  When  
additional  barrels  are  available  for  a  take-down  
firearm, these barrels are considered accessory 
barrels. See definition of accessory barrels.  
TOP-BREAK                              
A term used to describe a single-shot, multi-barrel
or revolver mechanism on which the barrel o
r
barrels  are  allowed  to  tip  down  at  the  muzzle
exposing  the  chamber  or  chambers  for  loading,  
unloading or extraction of cartridges.  
TOP-LEVER                                 
The lever located on the top of the breech end of
hinged-frame firearms that when pushed to one 
side will unlock the barrel
(s) from the receiver or 
frame and allow them to move (left, right, forward, 
rearward, tip-down or tip-up).  
TRIGGER                                 
That part of a firearm mechanism that is moved 
manually to cause the firearm to discharge.  
TRIGGER , RELEASE                       
An unconventional mechanism in which the firearm is
fired by the release, rather than by the pull 
of the trigger.  
TRIGGER, SET                              
Either a single or double trigger arrangement 
on which the required trigger pull force can be made 
very light by means of a "setting" mechanism.  
UNLOCKING                               
A stage in the cycle of operation of a firearm in which the bolt, breech block or standing breech is 
removed from fixed relationship with the chamber, so
as to permit the extraction and ejection cycle 
to take place after pressures have dropped to a safe operating level.  
VIERLING                                    
A four-barreled shoulder arm that usually 
has two smooth-bored and two rifled barrels.  
WATER TABLE                             
The flat portion of the receiver or frame on fir
earms that break open, ex
tending forward from, and 
is  approximately  at  right  angles  to,  the  standing-b
reech  face.  This  is  the  surface  on  which  the  
barrel flats rest when the action is closed.  
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