The M24 Sniper Weapon System (SWS) is the military and police version of the Remington Model 700 rifle, M24 being the model name assigned by the United States Army after adoption as their standard sniper rifle in 1988. The M24 is referred to as a "weapons system" because it consists of not only a rifle, but also a detachable telescopic sight and other accessories.
The M24 SWS has the "long action" bolt version of the Remington 700 receiver but is chambered for the 7.62×51mm NATO "short action" cartridge that has an overall length of 2.750 inches (69.85 mm). The "long action" allows the rifle to be re-configured for dimensionally larger cartridges up to 3.340 inches (84.84 mm) in overall length.
The M24 originally came tapped for the Leupold Ultra M3A 10×42mm fixed-power scope, which came with a circle-shaped mil-dot glass-etched reticle. This was later replaced in 1998 by the cheaper Leupold Mk 4 LR/T M1 10×40mm fixed-power scope with an elongated-shaped mil-dot wire reticle.
The first number is the scope's magnification (10) and the second number in millimeters (40mm) is the diameter of the objective lens. A fixed power scope has only one magnification (e.g., 10×) and a variable power scope can be adjusted to focus between a range of magnifications (e.g., 3–9× is adjustable from a minimum power of 3× to a maximum power of 9×). The rifle itself comes with a detachable Harris 9-13" 1A2-LM or Harris 9-13" 1A2-L bipod unit.
The M24 SWS was to be replaced with the M110 Semi-Automatic Sniper System, a contract awarded to Knight's Armament Company. However, the Army still continued to acquire M24s from Remington until February 2010 and upgraded to the A2 and M24E1 standard in many cases, continuing to serve. The Army chose to upgrade its entire M24 rifle fleet to the M2010 Enhanced Sniper Rifle, with the final M24 being converted in April 2014.