![PEO M4 Carbine RAS M68 CCO](https://upload.wikimedia.org/wikipedia/commons/6/68/PEO_M4_Carbine_RAS_M68_CCO.png)
Rail systems on firearms are straight mounting brackets (usually made of strips of metal or polymer) on the gun's
receiver,
handguard
A barrel shroud is an external covering that envelops (either partially or full-length) the barrel of a firearm, to prevent unwanted direct contact with the barrel (e.g. accidental collision with surrounding objects, or the user accidentally tou ...
or
fore-end stock to allow sliding/variable-position attachment of
Iron sights,
Scopes ,
Holographic Sightsand other
optical sight
A sight is an aiming device used to assist in visually aligning ranged weapons, surveying instruments or optical illumination equipments with the intended target. Sights can be a simple set or system of physical markers that have to be aligne ...
s options. .Along with accessories such as
tactical light
A tactical light is a flashlight used in conjunction with a firearm to aid low-light target identification, allowing the marksman, law enforcement officer or soldier to simultaneously aim a weapon and illuminate the target. Tactical lights can ...
s,
laser sights
Many scientific, military, medical and commercial laser applications have been developed since the invention of the laser in 1958. The coherency, high monochromaticity, and ability to reach extremely high powers are all properties which allow ...
,
vertical/angled foregrips and/or
bipod
A bipod is a V-shaped portable attachment that helps support and steady a device, usually a weapon such as a long gun or a mortar. The term comes from the Latin prefix ''bi-'' and Greek root ''pod'', meaning "two" and "foot" respectively.
Bip ...
s. Are examples of just a few options that may be used depending on a mission's need for the
M4 is
SOPMOD
The Special Operations Peculiar MODification (SOPMOD) kit is an accessory system for the M4A1 carbine, CQBR, FN SCAR Mk 16/17, HK416 and other weapons used by United States Special Operations Command (USSOCOM), though it is not specific to SO ...
, amongst many other accessories like sling attachment points (which may be ether ring, loop and/or
quick detach mounts using push button style hardware) to name just a few of the many options. An advantage with the multiple rail slots is the moveable positions to adjust for optimal placement of each item for each different user. Along with the ability to switch different items at different placements due to varying
eye relief {{Short description, Optical instrument
The eye relief of an optical instrument (such as a telescope, a microscope, or binoculars) is the distance from the last surface of an eyepiece within which the user's eye can obtain the full viewing angle. ...
s on
gun sights, scopes & optics. Tactical usage and
Shooting sports have both benefited from the extra options provided.
Rails as a term has evolved to cover both the actual rail pieces and the styles of handguards (or forearms) that are made with rails as the external surfaces. Original rails were a raised metal strip with the sides under cut, less standardized than the dovetail design, to allow hardware to slide on and be secured by means of compression only.
The firearm often associated with, and that has benefited from rails is the
M4 Carbine
A carbine ( or ) is a long gun that has a barrel shortened from its original length. Most modern carbines are rifles that are compact versions of a longer rifle or are rifles chambered for less powerful cartridges.
The smaller size and lighte ...
&
M16 family of later models/variants -A2 -A3 & -A4 . With equal and even more use due to additional
novelty item
A novelty item or simply novelty is an object which is specifically designed to serve no practical purpose, and is sold for its uniqueness, humor, or simply as something new (hence "novelty", or newness). The term also applies to practical items wi ...
s is the
AR-15
An AR-15-style rifle is any lightweight semi-automatic rifle based on the Colt AR-15 design. The original ArmaLite AR-15 is a scaled-down derivative of Eugene Stoner's ArmaLite AR-10 design. The then Fairchild Engine and Airplane Corporatio ...
. Most modern military and civilian
semi-automatic Firearm have rails that may replace original parts. Police and Military style firearms may include
Pistols,
PDW
Personal defense weapons (PDWs) are a class of firearms intended for self-defense and security rather than warfare and infantry. Most PDWs fire a small-caliber (less than ), centerfire bottleneck cartridge resembling a scaled-down intermediate ...
s,
Carbine
A carbine ( or ) is a long gun that has a barrel shortened from its original length. Most modern carbines are rifles that are compact versions of a longer rifle or are rifles chambered for less powerful cartridges.
The smaller size and lighte ...
s,
Rifles,
Submachine guns,
Light Machine Guns
A light machine gun (LMG) is a light-weight machine gun designed to be operated by a single infantryman, with or without an assistant, as an infantry support weapon. LMGs firing cartridges of the same caliber as the other riflemen of the sam ...
, and
Heavy machine gun
A heavy machine gun (HMG) is significantly larger than light, medium or general-purpose machine guns. HMGs are typically too heavy to be man-portable (carried by one person) and require mounting onto a weapons platform to be operably stable or ...
s . HMGs have started to include and use rail sections and options for attachments of optics. Civilian clone
Rifles are the largest adapters, while the
Crossbow
A crossbow is a ranged weapon using an elastic launching device consisting of a bow-like assembly called a ''prod'', mounted horizontally on a main frame called a ''tiller'', which is hand-held in a similar fashion to the stock of a long fire ...
s,
Hunting Rifles,
shot guns and
Handguns have started to come from the factory with rail sections ether attached and/or made structurally as part of the actual
Firearm.
Airsoft
Airsoft is a team game in which participants eliminate opposing players by tagging them out of play with spherical plastic projectiles shot with mock air weapons(usually powered by an electronic motor) called airsoft guns.
Although similar ...
and
Paintball
Paintball is a competitive team shooting sport in which players eliminate opponents from play by hitting them with spherical dye-filled gelatin capsules called paintballs that break upon impact. Paintballs are usually shot using low-energy a ...
clone weapons will also likely have rails.
Rail designs
The common types of rail systems for firearms are the
dovetail rail
A dovetail rail or dovetail mount can refer to several types of sliding rail system found on firearms primarily for mounting telescopic sights. Colloquially, the term ''dovetail rail'' usually refer to any straight mounting bracket with an inver ...
,
(including the
Soviet
The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen nation ...
variant known as the Warsaw Pact rail), the
Weaver rail
A Weaver rail mount is a system to connect telescopic sights (often via a scope mount) and other accessories to firearms and certain crossbows. It uses a pair of parallel rails and several slots perpendicular to these rails.
The later Picatinn ...
,
the
Picatinny rail
The Picatinny rail ( or ), or Pic rail for short, also known as a MIL-STD-1913 rail, 1913 rail or STANAG 2324 rail (cancelled), is a military standard rail interface system that provides a mounting platform for firearm accessories. It was ...
(also known as the MIL-STD-1913 or
STANAG
In NATO, a standardization agreement (STANAG, redundantly: STANAG agreement) defines processes, procedures, terms, and conditions for common military or technical procedures or equipment between the member countries of the alliance. Each NATO st ...
2324 rail),
the
NATO Accessory Rail
The NATO Accessory Rail (NAR), defined by NATO Standardization Agreement (STANAG) 4694, is a rail interface system standard for mounting accessory equipments such as telescopic sights, tactical lights, laser aiming modules, night vision devi ...
(also known as the STANAG 4694 rail), and newer "negative space" systems such as the VLTOR
KeyMod and the
Magpul
Magpul Industries Corporation is an American designer and manufacturer of high-tech polymer and composite firearms accessories like M-LOK. Magpul Industries takes its name from its first product, the MagPul (Magazine Puller), an accessory for th ...
M-LOK.
M-LOK vs KeyMod comparison 2017
/ref> There are also non-military designs used in shooting sports to attach slings and bipods such as UIT rail and the Freeland rail.
MIL-STD-1913 " Picatinny rails" date from the mid-1990s and have very strict dimension and tolerance standards.
The Picatinny has rail of very similar profile to the Weaver, but the slot width is 0.206 in (5.23 mm), and by contrast with the Weaver, the spacing of slot centers is consistent, at 0.394 in (10.01 mm). Many rail-grabber-mounted accessories can be used on either type of rail, and accessories designed for a Weaver system will generally fit Picatinny rails - although not ''vice versa
References
Additional references
*
*
{{Latin phrases
Lists of Latin phrases, V
ca:Locució llatina#V
da:Latinske ord og vendinger#V
fr:Liste de locutions latines#V
id:Daftar frasa Latin#V
it:Locuzioni latine#V
nl:Lijst van Latijns ...
''. The Picatinny locking slot width is and the spacing of slot centers is .["Picatinny Rails, Weaver Rails, What’s The Difference?"](_blank)
Brownells Because of this, with devices that use only one locking slot, Weaver devices will fit on Picatinny rails, but Picatinny devices will not always fit on Weaver rails.
Compatibility
Adapters to other types of rail interfaces may be used for legacy issues and/or to change the surface texture, abrasiveness and/or overall outer circumference of the entire rails system for fit of the hand. Dovetail rail
A dovetail rail or dovetail mount can refer to several types of sliding rail system found on firearms primarily for mounting telescopic sights. Colloquially, the term ''dovetail rail'' usually refer to any straight mounting bracket with an inver ...
, Weaver and Picatinny
The Picatinny Arsenal ( or ) is an American military research and manufacturing facility located on of land in Jefferson and Rockaway Township in Morris County, New Jersey, United States, encompassing Picatinny Lake and Lake Denmark. The A ...
are all outward or raised attachment surfaces. While M-Lok and KeyMod have smooth surfaces with different standards & styles of holes cut into their assembles to place the attachment hardware internally. Both of these styles of features are often on and/or in the hand guards . All make the mounting and dismounting of these objects significantly easier. Items may be fasten by threaded bolts, requiring the use of a screwdriver or allen wrench, with some tool free variations of a Thumb screws or Thumb nuts, may have threaded quick disconnect lever that pulls the hardware and plates together against the rails. During firearm recoil the accessory may slide within that section of rail. To help avoid this, when tightening slide the device forward in the placement slots so the section of bolt is against the vertical/forward section of rail slots.
Usage
Rail systems usually are based on the handguard
A barrel shroud is an external covering that envelops (either partially or full-length) the barrel of a firearm, to prevent unwanted direct contact with the barrel (e.g. accidental collision with surrounding objects, or the user accidentally tou ...
of a weapon and/or the Upper receiver. On modern pistols they are on the underside of the barrel. Rails on rifles usually start off at top dead center or 12 o'clock with the next placement at bottom 180° degrees or at 6 o'clock. on the forward section, away from the buttstock. With both sides 3 o'clock & 9 'o clock or 90° degrees each side of top center 0°/360° degrees becoming the 3rd & 4th most common. 1 o'clock or 11'o'clock is popular for the flashlight with a tape switch location placed on user preference. There may be additional attachment rails or holes at each 45 °degree angle position running partially or entirely the length of the handguard.
On the Kalashnikov rifle
A Kalashnikov (Калашников) rifle is any one of a series of automatic rifles based on the original design of Mikhail Kalashnikov. They are officially known in Russian as "Avtomát Kaláshnikova" ( rus, Автома́т Кала́шник ...
s AK style/family the Warsaw rail is attached to the left side of the receiver when viewed from the rear . With more modern versions adding Picatinny style rails on to the sides of the handguards of the rifles for the mounting of addition equipment. Due to updating equipment, both styles may be found on some Warsaw Pact weapons.
Modern designed firearms often include rails made into the body, instead of being an added on modification. Older firearms may need permanent modifications of having holes drilled and tapped for screw threads to fasten the rail sections to the firearm. This is easier than milling out a dove tail slot for placement of a gun sight's parts.
Optics like scopes, reflex sights, holographic sights, red dot magnifiers, and night vision or thermal sights may be placed between the iron sights. Rail section may also come in various heights to help align equipment. Which may align with the original iron sights inline or below an illuminated optic's center dot, ring or chevron
Chevron (often relating to V-shaped patterns) may refer to:
Science and technology
* Chevron (aerospace), sawtooth patterns on some jet engines
* Chevron (anatomy), a bone
* '' Eulithis testata'', a moth
* Chevron (geology), a fold in rock ...
. This is referred to as Absolute or lower 1/3 Co-witness respectively. In addition to height variations some rail brackets may be offset at various degrees, 22.5°, 45°, and 90° are the most common, to place accessories and/or backup folding collapsible iron sights. So they are out of the line sight on the top of the firearm and/or to decrease the outer profile edge's size. Then the original sights are a backup if the electronic optic should fail. The rail section may also move a weapon-mounted lights forward so the flashlight (UK torch) does not shine and reflect back on the firearm directly. Creating shadows and visual impairment from this illumination.
The amount of rail space allows adjustment and personal optimization of each device and tool attached for the user. As designs have advance the amount of space has succeeded the actual need of placement space. Thus rail covers and protectors may be added, to prevent snagging on gear and/or plant foliage.
The six common types of rail systems for firearms are the Dovetail rail
A dovetail rail or dovetail mount can refer to several types of sliding rail system found on firearms primarily for mounting telescopic sights. Colloquially, the term ''dovetail rail'' usually refer to any straight mounting bracket with an inver ...
, Weaver rail
A Weaver rail mount is a system to connect telescopic sights (often via a scope mount) and other accessories to firearms and certain crossbows. It uses a pair of parallel rails and several slots perpendicular to these rails.
The later Picatinn ...
, Warsaw Pact rail
A dovetail rail or dovetail mount can refer to several types of sliding rail system found on firearms primarily for mounting telescopic sights. Colloquially, the term ''dovetail rail'' usually refer to any straight mounting bracket with an inver ...
, Picatinny rail
The Picatinny rail ( or ), or Pic rail for short, also known as a MIL-STD-1913 rail, 1913 rail or STANAG 2324 rail (cancelled), is a military standard rail interface system that provides a mounting platform for firearm accessories. It was ...
, KeyMod and M-LOK.
Future rails systems will have the option of carry power to supply the needs of the increasing electronics mounted to aid the shooter and/or soldier. Standards are still being determined for multiple countries. An example of such is NATO standards NATO Accessory Rail
The NATO Accessory Rail (NAR), defined by NATO Standardization Agreement (STANAG) 4694, is a rail interface system standard for mounting accessory equipments such as telescopic sights, tactical lights, laser aiming modules, night vision devi ...
which is continued improvement and standardization of the Picatinny rail
The Picatinny rail ( or ), or Pic rail for short, also known as a MIL-STD-1913 rail, 1913 rail or STANAG 2324 rail (cancelled), is a military standard rail interface system that provides a mounting platform for firearm accessories. It was ...
.
See also
* Rail Integration System (RIS)
* Dovetail rail
A dovetail rail or dovetail mount can refer to several types of sliding rail system found on firearms primarily for mounting telescopic sights. Colloquially, the term ''dovetail rail'' usually refer to any straight mounting bracket with an inver ...
* Weaver rail
A Weaver rail mount is a system to connect telescopic sights (often via a scope mount) and other accessories to firearms and certain crossbows. It uses a pair of parallel rails and several slots perpendicular to these rails.
The later Picatinn ...
* Warsaw Pact rail
A dovetail rail or dovetail mount can refer to several types of sliding rail system found on firearms primarily for mounting telescopic sights. Colloquially, the term ''dovetail rail'' usually refer to any straight mounting bracket with an inver ...
* Picatinny rail
The Picatinny rail ( or ), or Pic rail for short, also known as a MIL-STD-1913 rail, 1913 rail or STANAG 2324 rail (cancelled), is a military standard rail interface system that provides a mounting platform for firearm accessories. It was ...
* NATO Accessory Rail
The NATO Accessory Rail (NAR), defined by NATO Standardization Agreement (STANAG) 4694, is a rail interface system standard for mounting accessory equipments such as telescopic sights, tactical lights, laser aiming modules, night vision devi ...
* KeyMod
* M-LOK
* UIT rail
References
{{DEFAULTSORT:Rail System (Firearms)
Firearm components
Mechanical standards