page_title: Rail system (firearms)
section_title: Usage
hierarchical_section_title: Rail system (firearms) / Usage
caption_attribution_description: English: A Ranger with 2nd Battalion, 75th Ranger Regiment, provides overwatch security on an objective during a mission in Iraq, 2006.
context_page_description: Rail systems on firearms are straight mounting brackets on the gun's receiver, handguard or fore-end stock to allow sliding/variable-position attachment of optical sights and accessories such as tactical lights, laser sights, vertical/angled foregrips and bipods. An example of just a few options that may be used depending on a mission's need for the M4 is SOPMOD. 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 reliefs 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 piece and the styles of handguards that are made with rails as the external surfaces.
context_section_description: Rail systems usually are based on the handguard 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 atape 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 rifles 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.
  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 section(s) to the firearm. This is easier than milling out a dove tail slot for placement of a gun sights parts.
  Optics like scopes, Reflex Sight, and Red Dot 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. 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°, & 90° are the most common, to place accessories and/or back up 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 back up 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, Weaver rail, Warsaw Pact rail, Picatinny rail, 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 which is continued improvement and standardization of the Picatinny rail.
caption: A U.S. Army Ranger, armed with a M249 light machine gun, Showing multiple Rails and Accessories in overwatch security on an objective during a mission in Iraq, 2006.
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