M240 American 7.62mm General-Purpose Machine Gun
M240
Hezbollah Proliferation. The M240, officially the Machine Gun, 7.62 mm, M240, is the US military designation for the FN MAG (Mitrailleuse A Gaz, 'gas-operated machine gun'; alternatively, Mitrailleuse d'Appui General 'machine gun, support, general'), a family of belt-fed, gas-operated medium machine guns that chamber the 7.62×51mm NATO cartridge. The M240 has been used by the United States Armed Forces since the late 1970s. It is used extensively by infantry, most often in rifle companies, as well as on-ground vehicles, watercraft, and aircraft. Despite being heavier than some comparable weapons, it is highly regarded for reliability and its standardization among NATO members is a major advantage. All variants are fed from disintegrating belts and are capable of firing most types of 7.62 mm (.30/.308 cal) NATO ammunition. M240 variants can be converted to use non-disintegrating belts. There are significant differences in weight and some features among some versions which restrict the interchangeability of parts. The M240s used by the US military are currently manufactured by FN America, the American subsidiary of FN Herstal. The M240B and M240G are usually fired from an integrated bipod, a tripod, or a vehicular mount; regarding tripod use, the U.S. Army primarily uses the M192 Lightweight Ground Mount, while the U.S. Marine Corps uses the M122A1 tripod, a slightly updated M2 tripod. Loading the M240 can be done either with the bolt forward or to the rear. If the bolt is to remain forward, the operator will then load the rounds into the feeding block (feed tray cover closed); or will open the feed tray cover, load the rounds onto the feeding tray, then close the feed tray cover. The charging handle will then be pulled to the rear, which locks the bolt to the rear. The weapon is then placed on the safe and the charging handle is then placed back to the forward position (this is spring-loaded on the tank-mounted variation). The weapon is now ready for operation. The weapon fires from the open bolt position, meaning that the bolt is held to the rear and only moves forward as it is firing around. The firing pin is static and the bolt moves around the firing pin, circumventing any need for a hammer. A sear is used to time the internal mechanisms of the weapon to provide a consistent rate of fire, ensuring proper function and accuracy. However, firing from an open bolt also provides the possibility of an accidental discharge due to a bolt override. This happens when there is enough force for the bolt to jump over the sear and fire without the trigger being pulled. The safety of the weapon cannot stop this from happening. The safest way to protect against this is to leave the bolt forward on the weapon until the operator is ready to fire the weapon; then charge the weapon and fire. Clearing the weapon is performed by ensuring that the bolt is locked to the rear and the weapon is safe. The top cover is then lifted, the remaining belt (if any) is swept out of the feed tray, and the feed tray is lifted to visually inspect the chamber and the face of the bolt. Any links or brass casings are removed. The weapon is now clear. In the extremely unlikely event that a live round is on the bolt face, it is knocked loose with a cleaning rod or another rigid object. If there is a live round lodged in the barrel, the operator must immediately decide if the barrel is hot enough that there is a chance of it cooking off. If there is, he will immediately move his face away from the opening of the weapon; and aim the gun in a direction that is perceived to take the least amount of damage and/or casualties should the event of a cook-off occur. He should then wait for the barrel to cool off before attempting to remove it. He can also attempt to extract the round by closing the cover, taking the weapon off of the safe, and pulling the trigger. This will likely cause the weapon to fire, so care should be made in ensuring that the weapon is first pointed in a safe direction. The rate of fire may be controlled by three different gas regulator settings. The first setting allows the weapon to cycle at 650–750 rounds per minute, the second set is 750–850 rounds per minute, and the third setting is 850–950 rounds per minute. These settings are changed by dismounting the barrel, removing the gas regulator collar, and turning the gas regulator to allow more or less gas to move through the weapon system. It is generally performed only when necessary to return the gun to operation after fouling has caused sluggish operation and there is no time to properly clean the weapon. The barrels can be exchanged rapidly, thanks to a barrel release button located on the left side of the weapon. The weapon is cleared first and then the button is held down, while the barrel's carrying handle is moved from the right side of the weapon to the center, unlocking it from the receiver. At this point, the button is released and the barrel is then pulled free of the receiver and placed to the side. The new barrel is inserted into the receiver and then the carrying handle is shifted to the right, locking it into place. Headspace is set by counting the clicks as the barrel is locked down and should be between two and seven clicks. During prolonged firing, care must be taken to not allow exposed skin to come in contact with the weapon. The barrels can become hot enough to inflict second-degree burns instantly without becoming visibly different. These hot barrels glow brightly to anyone using any sort of optics sensitive to infrared radiation, such as night vision devices.