page_title: AK-47
section_title: Operating mechanism
hierarchical_section_title: AK-47 / Design / Operating mechanism
caption_attribution_description: English: A schematic showing the workings of an assault rifle (Chinese type 56, AK47). The schematic was based on an image in the book: "Infantry weapons" by Chris Bishop.
context_page_description: The AK-47, officially known as the Avtomat Kalashnikova, is a gas-operated, 7.62×39mm assault rifle, developed in the Soviet Union by Mikhail Kalashnikov. It is the originating firearm of the Kalashnikov rifle family. 47 refers to the year it was finished.
  Design work on the AK-47 began in 1945. In 1946, the AK-47 was presented for official military trials, and in 1948, the fixed-stock version was introduced into active service with selected units of the Soviet Army. An early development of the design was the AKS, which was equipped with an underfolding metal shoulder stock. In early 1949, the AK-47 was officially accepted by the Soviet Armed Forces and used by the majority of the member states of the Warsaw Pact.
  Even after seven decades, the model and its variants remain the most popular and widely used rifles in the world because of its reliability under harsh conditions, low production costs compared to contemporary Western weapons, availability in virtually every geographic region, and ease of use.
context_section_description: To fire, the operator inserts a loaded magazine, pulls back and releases the charging handle, and then pulls the trigger. In semi-automatic, the firearm fires only once, requiring the trigger to be released and depressed again for the next shot. In fully automatic, the rifle continues to fire automatically cycling fresh rounds into the chamber until the magazine is exhausted or pressure is released from the trigger. After ignition of the cartridge primer and propellant, rapidly expanding propellant gases are diverted into the gas cylinder above the barrel through a vent near the muzzle. The build-up of gases inside the gas cylinder drives the long-stroke piston and bolt carrier rearward and a cam guide machined into the underside of the bolt carrier, along with an ejector spur on the bolt carrier rail guide, rotates the bolt approximately 35° and unlocks it from the barrel extension via a camming pin on the bolt. The moving assembly has about 5.5 mm (0.2 in) of free travel, which creates a delay between the initial recoil impulse of the piston and the bolt unlocking sequence, allowing gas pressures to drop to a safe level before the seal between the chamber and the bolt is broken. The AK-47 does not have a gas valve; excess gases are ventilated through a series of radial ports in the gas cylinder. The Kalashnikov operating system offers no primary extraction upon bolt rotation, but uses an extractor claw to eject the spent cartridge case.
caption: The gas-operated mechanism of a Norinco AK-47
exif: {"Image ImageDescription": "KONICA MINOLTA DIGITAL CAMERA", "Image Make": "KONICA MINOLTA", "Image Model": "DiMAGE Z6", "Image Orientation": "Horizontal (normal)", "Image XResolution": "72", "Image YResolution": "72", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "GIMP 2.6.4", "Image DateTime": "2009:12:27 14:47:16", "Image YCbCrPositioning": "Centered", "Image ExifOffset": "380", "Image PrintIM": "[80, 114, 105, 110, 116, 73, 77, 0, 48, 51, 48, 48, 0, 0, 0, 5, 0, 1, 0, 22, ... ]", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail Orientation": "Horizontal (normal)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "34452", "Thumbnail JPEGInterchangeFormatLength": "3614", "Thumbnail YCbCrPositioning": "Centered", "EXIF ExposureTime": "1/80", "EXIF FNumber": "4", "EXIF ExposureProgram": "Program Normal", "EXIF ISOSpeedRatings": "50", "EXIF ExifVersion": "0220", "EXIF DateTimeOriginal": "2009:12:23 15:21:12", "EXIF DateTimeDigitized": "2009:12:23 15:21:12", "EXIF ComponentsConfiguration": "YCbCr", "EXIF BrightnessValue": "31/5", "EXIF ExposureBiasValue": "0", "EXIF MaxApertureValue": "3", "EXIF MeteringMode": "Pattern", "EXIF LightSource": "Unknown", "EXIF Flash": "88", "EXIF FocalLength": "375/64", "EXIF SubjectArea": "[1408, 1056, 320, 320]", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "2748", "EXIF ExifImageLength": "872", "Interoperability InteroperabilityIndex": "R98", "Interoperability InteroperabilityVersion": "[48, 49, 48, 48]", "EXIF InteroperabilityOffset": "34304", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Auto Exposure", "EXIF WhiteBalance": "Auto", "EXIF DigitalZoomRatio": "0", "EXIF FocalLengthIn35mmFilm": "35", "EXIF SceneCaptureType": "Standard", "EXIF GainControl": "None", "EXIF Contrast": "Normal", "EXIF Saturation": "Normal", "EXIF Sharpness": "Normal", "EXIF SubjectDistanceRange": "1"}