Rail integration system

Rail systems are usually made of strips of metal or polymer screw-fastened onto the gun's receiver, handguard, or fore-end stock to allow variable-position attachments.

Original rails were a raised metal strip with the sides undercut, less standardized than the dovetail design, to allow hardware to slide on and be secured by means of compression only.

There may be additional attachment rails or holes at each 45° angle position running partially or entirely the length of the handguard.

On the Kalashnikov rifles, 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 onto the sides of the handguards of the rifles for the mounting of additional equipment.

The amount of rail space allows adjustment and personal optimization of each device and tool attached for the user.

Basic systems such as small rails (20mm is standard) with holes machined in them to be screwed onto the existing hand-guard of a rifle can cost as little as US $25 to US $40.

The prevalence of rails on modern firearms compared to past designs is largely owed to the increasing popularity and availability of attachments such as sights.

Even ranged weapons that are not firearms, such as bow and arrow, crossbow, airsoft gun, and paintball marker.