AR-15
| AR-15 | |
|---|---|
| Country | US |
| Type | automatic rifle / semi-automatic rifle |
| Inventor | |
| Date of design | 1950s |
| Service duration | 1960s |
| Cartridge | 5.56 mm |
| Action | Gas-actuated |
| Rate of fire | |
| Muzzle velocity | |
| Effective range | |
| Weight (Unloaded) | 3.4 kg |
| Length | 39 in (991 mm) |
| Barrel | 20 in (508 mm) |
| Magazine capacity | box magazine |
| Viewing sights | iron |
| Variants | |
| Number built | |
The AR-15 is a lightweight, magazine-fed, air-cooled, autoloading centerfire Rifle designed by Eugene Stoner of the ArmaLite corporation who developed it as a smaller-caliber version of the AR-10.
History
Armalite sold its rights to the AR-10 and AR-15 to Colt in 1959 after which the AR-15 was adopted by the United States military under the designation M16. Colt continued to use the AR-15 trademark for its semi-automatic variants. Today the AR-15 and its variations are manufactured by many companies and have captured the affection of sport shooters and police forces around the world due to their low cost, accuracy, and modularity. Please refer to the M16 for a more complete history of the development and evolution of the AR-15 and derivatives.Some revolutionary or otherwise notable features of the AR-15:
- Aircraft grade aluminum receiver
- Modular design allows for a variety of accessories, renders repair easier
- Small caliber, high velocity round
- Synthetic stock and grips do not warp or splinter
- Front ironsight adjustable for elevation
- Rear ironsight adjustable for Windage and distance
- Wide array of optical devices available in addition to or as replacements of ironsights
In the United States, variants with certain features were prohibited for new sales to civilians during the period 1994-2004 by the Violent Crime Control and Law Enforcement Act of 1994, under the provision known as the Assault Weapons Ban.
Semi-automatic and automatic variants of the AR-15 are effectively identical in appearance. Automatic variants have a rotating Selective fire switch, allowing the operator to select between three modes: safe, semi-automatic, and either automatic or three round burst depending on model. In semi-automatic only variants, the selector only rotates between safe and semi-automatic.
Technical data
- Caliber: .223 Rem, 5.56 x 45 mm NATO (many variants in other calibers are made by various manufacturers)
- Length: 39 in (991 mm)
- Mass: 3.4 kg (7.5 lb)
- Barrel: 20 in (508 mm) standard, 16 in (406mm) and 14.5(368mm) common
- Rifling: 1:12 for original 55 grain (3.6 g) bullets. Newer configurations use 1:9 and 1:7 twist rates. There is much controversy and speculation as to how differing twist rates affect ballistics and terminal performance with varying loads, but heavier projectiles tend to perform better with faster rifling rates.
- Magazine capacity: 10, 20, 30; 90, 100 (see below)
Standard issue magazines are 20 or 30 round double stack magazines; drum magazines in 90 and 100 round capacities also exist. Low-capacity magazines are available to comply with some areas' legal restrictions or for hunting.
Aftermarket "uppers" that incorporate barrels of different weights, lengths, and can handle different caliber ammo abound for this rifle. They are very easily installed, due to the rifle's modular design. Prices tend to be reasonable.
Variants
The AR15 rifle is available in a wide range of configurations from a number of manufacturers. These configurations range from short carbine-length models with features such as adjustable length stocks and optical sights, to heavy barrel models modified for long range Prairie dog hunting and long range military and civilian competition. The Bushmaster XM-15 is a semi-automatic rifle version of the AR-15 made in several different calibers by Bushmaster Firearms, Inc.