Letter T Firearms Glossary

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Takedown

A firearm that can be separated into (at least) two subassemblies in order to make a shorter package than when put together, without tools. There is no specific requirement regarding how this disassembly must be accomplished; the mechanical design is up to the creativity of the maker. This arrangement allows for more convenient transportation of a firearm, but with rifles, where the action normally separates from the barrel, usually at a small sacrifice in accuracy. Takedown firearms can also be called take-apart firearms. Good examples of a takedown guns are the Henry AR-7 Survival Rifle, the Ruger 10/22 Takedown or the TNW Aero.

Tang

The recurved top part of a semi-automatic handgun's grip at the point where it meets the slide. On long guns, the tang is the top strap used to screw the receiver to the stock.

Tangent Sight

A style of rear sight, typically used on rifles for either slow-moving bullets or for long ranges, whereby a ladder may be raised from flush with the barrel to a vertical position, and which incorporates a sliding crossbar which may be moved vertically in order to achieve significant elevation.

Tap, Rack, Bang

The slang term for the procedure to clear a misfeed. To clear a misfeed, tap the base of the magazine firmly to be sure it is properly seated, rack the slide to eject an empty case or feed a new round, and assess to be sure your target still needs shooting. If it does, pull the trigger to create the bang.

Telescopic Sight

An optical sight, offering some magnification, often variable, with some kind of adjustable aiming grid inside (a reticle), which when mounted on a firearm, usually a rifle, makes sighting easier.

Terminal Ballistics

A sub-field of ballistics, is the study of the behavior of a projectile when it hits its target.

Three Gun

A shooting sport where cometitors use three different guns on each stage of the competion; shotgun, rifle and handgun.

Three Rules

The NRA teaches the Three Basic Rules of Safe Gun Handling. There are additional rules, but these are the three that if any two are followed, nobody will be hurt. However, obviously, all three should always be followed.

Rule One: ALWAYS keep the gun pointed in a safe direction.
Rule Two: ALWAYS keep your finger off the trigger until ready to shoot.
Rule Three: ALWAYS keep the gun unloaded until ready to use.
The NRA established these three rules in 1871. They were created to be easy to understand and remember, ensuring the highest possible level of firearm safety.
See also The Four Rules

Throat

The beginning of the bore of a rifled firearm. The transition between the chamber and the rifling. The area most vulnerable to erosion from high velocity cartridges.

Throat Erosion

The wearing of the portion of the barrel where the gas pressure and heat is highest as the projectile leaves the chamber. The greater the chamber pressure the more rapid throat erosion occurs which is compounded by rapid firing which heats and weakens the steel.

Thumb Safety

An external, manual safety which is typically disengaged with the firing-hand thumb.

Thumbhole Stock

A rifle stock, with a sculptured throughole at the wrist for the thumb, said to be more ergonometric to hold than a traditional stock. Apart from being slower to mount, totally useless for a counter-dexterous person, it is so unmitigatedly graceless as to be beneath consideration.

Thunder

With the execption of the BP model series, Thunder is the name of all of Bersa's pistols. The line currently consists of three frames.

• The Thunder .380 series, which is a very reliable and good looking compact blowback system .380 acp pistol (there is also a .22lr version).
• The full size Thunder Pro series (avalable in 9mm and .40 S&W) is a locked breech design.
• The Thunder Ultra Compact Pro series, locked breech, short recoil design which is more of a commander size Thunder Pro (available in 9mm, .40 S&W, and .45 acp).
The Bersa Thunders are well known among firearms enthusiasts for being extremely high quality guns at reasonable prices.

Timing

The proper adjustment of the various interrelated moving parts of a gun so that every operation works in proper sequence, such as that the two ejectors of a double gun kick out the spent cases at the same instant and with the same force.

Toe

The bottom of the butt-end of a gun stock.

Toplever

A lever on a break-open gun mounted to the top of the receiver which, when pushed with the thumb (normally) to the right, operates (usually) a Scott Spindle, which in turn withdraws (usually) a Purdey Underbolt from the bites in the lumps of the barrels, allowing them to hinge downwards and the gun to open.

Topstrap

The part of a revolver's frame connecting the recoil shield to the barrel-mounting recess; adding considerable strength compared to that of early black powder Colt revolvers, and providing a base for a rear sight.

Touch Hole

A small orifice at the breech end of the barrel of a muzzle-loading firearm through which the exploding priming charge is conducted from the flash pan to the main charge.

Touchmark

A craftsman's signature stamp, discretely placed to identify his work.

Trace

Visible disturbance in the air by a bullet. Typically this takes the form of image distortion that persists for a fraction of a second in the shape of an inverted V similar to that of a boat wake.

Tracer

A type of ammunition that utilizes a projectile or projectiles that contain a compound in its base that burns during its flight to provide a visual reference of the projectile's trajectory.

Traditional Isosceles

In the Traditional Isosceles stance, Both arms are stretched almost equally forward with the gun centered forward. The knees are straight or only slightly flexed, and the entire body is upright and parallel to the target. This is an acceptable range stance provided recoil control is not an issue and you don't need to make rapid follow-up shots. However, if you are practicing for self-defense, you will probably want to use the Modern Isosceles stance stance instead.

Trajectory

The arc described by a projectile (or a load of shot) after it exits the muzzle of a firearm. Falling objects accelerate downwards at a rate of 32 feet per second, per second. The faster a projectile travels, the greater the distance it can cover in a given time before dropping too far. Hence, the higher the velocity of a bullet, the flatter the trajectory it will achieve.

Trap

A game of competitive clay pigeon shooting on a formally designed layout. In plan view, one launching machine is located 16 yards in front of a straight line, firing rising targets perpendicular to and away from that line. Five competitors shoot five individual targets at each of five stations along that line. Although each target is presented at slightly randomized vectors, trap emphasizes generally a single type of shot, outgoing and rising, and targets are broken at generally longer ranges than Skeet.

Trap Gun

A shotgun, often with only a single relatively-long barrel, with relatively tight choke boring and a relatively high-combed stock used for shooting clay pigeons in the game of Trap, where the birds are launched at least 16 yards ahead, usually rising and going away from the shooter at relatively low angular velocity. To better absorb recoil, a trap gun is normally heavier than a field gun because one shoots a lot but walks only a little.

Trapdoor

As in Trapdoor buttplate or Trapdoor Pistol Grip Cap, one of these articles of furniture including a hinged plate, covering a small compartment below in which may be stored several extra cartridges, sight bits, extra springs or pins, cleaning rod, etc.

Trigger

The small lever on a cartridge firearm, which one pulls to cause the spring-loaded firing pin to impact the primer, causing the gun to discharge. Normally, the trigger simply connects to the sear. Pulling the trigger moves the sear out of its notch, releasing the spring-loaded hammer to strike the firing pin which in turn strikes the primer; or the coilspring-loaded firing pin directly. Other, often-Germanic systems have their own miniature lockwork which, when cocked, allows an exceedingly light trigger pull to discharge the firearm, a setting that would be perilous to carry in the field.

Trigger Bar

On a semi-automatic pistol, or any other firearm in which the trigger is at some distance from the sear, this is an intermediate piece connecting the two parts.

Trigger Break

The point at which the trigger allows the hammer to fall, or releases the striker, so that the shot fires. The ideal trigger break is sudden and definite. "Like a glass rod" is the cliche term shooters use to describe the ideal crisp, clean break.

Trigger Control

Not putting your finger on the trigger until your sights are on target, then pulling the trigger smoothly, and following through by realigning the sights before allowing your finger to come off the trigger.

Trigger Group

The entire collection of moving parts which work together to fire the gun when the trigger is pulled. It may include trigger springs, return springs, the trigger itself, the sear, disconnectors, and other parts.

Trigger Guard

Usually a circular or oval band of metal, horn or plastic that goes around the trigger to provide both protection and safety in shooting circumstances. The shooter's finger should never be within the trigger guard unless the sights are on target and the shooter has made the decision to fire.

Trigger Jerk

Yanking the trigger back abruptly, thus pulling the muzzle of the gun downward at the moment the shot fires.

Trigger Lock

A locking device, usially a clable with a padlock that you put on a firearm to render it unable to be fired buy running it through the magazine well and out the ejection port.

Trigger Pull

The entire process of moving the trigger from its forward-most position to its rearward-most position, causing the hammer to fall and the shot to fire.

Trigger Pull Weight

The ammount pressure needed (measured in pounds) for the trigger finger must put on the trigger before the gun will fire. Trigger pull weight is measured by the number of pounds and ounces of pressure required to pull the trigger past the break.

Trigger Safety

An external, passive safety which can be found on the face of some trigger designs (most notably found on Glock firearms). It is intended to prevent the trigger from being pulled by objects which find their way into the trigger guard area.

Trigger Scale

A specialized type of hanging scale designed to test trigger pull weight.

Trigger Slap

An uncomfortable sensation caused by the trigger springing back into the shooter's trigger finger while firing.

Tunnel Claw Mount

A claw [scope] mount with openings through which a shooter can use a rifle's iron sights without removing the scope.

Turk's Head

A tip for a cleaning rod, a jag, with spirally-radial wires for vigorously scrubbing a gun's bore.

Turn-Bolt Action

A bolt action which is locked by pressing the bolt handle in and down, thereby turning its locking lugs into the receiver.

Twilight Sight

A rifle front sight with a extra-large, folding bead. Typically, in addition to the normal fine bead (which allows for more precision) the larger bead, while at a cost of potential accuracy, is more readily acquired in marginal light. Also called a Gloaming sight

Twilight Sight

A rifle front sight with a extra-large, folding bead. Typically, in addition to the normal fine bead (which allows for more precision) the larger bead, while at a cost of potential accuracy, is more readily acquired in marginal light. Also called a Gloaming sight

Twist

The length, within a rifled barrel, required to accomplish one full rotation. 1:12 Twist, means a bullet passing down the bore would complete one revolution in twelve inches. 1:7 Twist, means a bullet passing down the bore would complete one revolution in seven inches, which makes it a tighter twist than 1:12. Different weights of bullet require appropriate rates of twist.