AR-15–style rifle
The Colt model removed the selective fire feature of its predecessor, the original ArmaLite AR-15, which is a scaled-down derivative of the AR-10 design (by Eugene Stoner).
ArmaLite sold the patent and trademarks for both to Colt's Manufacturing Company in 1959 after the military rejected the design in favor of the M14.
[1] From 1994 to 2004, the Federal Assault Weapons Ban restricted the sale of the Colt AR-15 and some derivatives in the United States, although it did not affect rifles with fewer listed features.
[19][16] Due to financial problems and limitations in terms of manpower and production capacity, ArmaLite sold the AR-15 and AR-10 designs and trademarks to Colt in 1959.
[21] After Colt's patents expired in 1977, an active marketplace emerged for other manufacturers to produce and sell their own semi-automatic AR-15–style rifles.
[28][29] Once a firearm has been configured as a rifle, whether through modification or originally manufactured that way, it can't be converted back into a pistol.
As civilian ownership of AR-15–style rifles became sufficient to create a market for improvements, numerous manufacturers began producing aftermarket parts—including parts with features not found on basic AR-15 rifles, and individuals with basic mechanical aptitude can often substitute these pieces for original equipment without needing a gunsmith.
End users may install their own choice of fire control group and lower parts kit.
[43] A few manufacturers have made full upper receivers,[44] or even "bufferless" bolt carrier systems where the buffer system is wholly contained in the upper receiver, and therefore does not use the buffer tube, which allows for firing while the stock is in the folded position, or removal of the stock altogether.
This Stoner bolt and carrier piston system has the disadvantage of venting un-burned smokeless powder residue into the receiver where it may ultimately accumulate in quantities causing malfunctions.
To theoretically reduce the risk of slam-firing, the HK416 and its civilian variant MR556 feature a proprietary firing pin safety in the bolt.
[49] Most rifles eject spent cartridges from the right side of the receiver away from right-handed shooters who place the butt against the right shoulder while sighting with the right eye and using a finger of the right hand to pull the trigger.
[66] While AR-15–style rifles are banned in New York City, the FightLite SCR has been explicitly allowed, even though it accepts standard AR-15 upper receivers.
[72] These are most commonly marketed in jurisdictions where ownership of semi-automatic centerfire rifles are heavily restricted, such as in the United Kingdom and Australia.
Most components are interchangeable between semi-auto and select fire rifles including magazines, sights, upper receiver, barrels and accessories.
Parts changed include the lower receiver, bolt carrier, hammer, trigger, disconnector, and safety/mode selector.
On the select-fire version, the hammer has an extra spur which interacts with the additional auto-sear that holds it back until the bolt carrier group is fully in battery, when the automatic fire is selected.
[77][78][79][80] As designed by Colt, the pins supporting the semi-auto trigger and hammer in the lower receiver are larger than those used in the military rifle to prevent interchangeability between semi-automatic and select-fire components.
[81][82] The first version produced for commercial sale by Colt was the SP1 model AR-15 Sporter in .223 Remington, with a 20-inch (51 cm) barrel and issued with five-round magazines.
[21] Initial sales of the Colt AR-15 were slow, primarily due to its fixed sights and carry handle that made scopes difficult to mount and awkward to use.
These carbines have become popular for police use in confined urban spaces, and the collapsible buttstock compensates for the additional thickness of body armor.
[92] Construction with lightweight polymers and corrosion-resistant alloys makes these rifles preferred for hunting in moist environments with less concern about rusting or warping wood stocks.
[102] According to a 2013 analysis by Mayors Against Illegal Guns, 14 out of 93 mass shootings involved high-capacity magazines or assault weapons.
[103] Nevertheless, AR-15–style rifles have played a prominent role in many high-profile mass shootings in the U.S.[104] and have come to be widely characterized as the weapon of choice for perpetrators of these crimes.
[118][119][120] As a result of the Christchurch mosque shootings with an AR-15 during Friday Prayer on March 15, 2019, the New Zealand government enacted a law to ban semi-automatic center-fire rifles, magazines holding more than 10 rounds, and parts that can be used to assemble prohibited firearms.
[121][122] After the 2020 Nova Scotia attacks, the deadliest rampage by a single person in Canadian history,[123] Canada banned a class of firearms, including the AR-15.
