The AR-15 is a lightweight, 5.56×45mm, magazine-fed, gas-operated semi-automatic rifle. The upper receiver incorporates the fore stock, the charging handle, the forward assist, the gas operating system, the barrel, the bolt and bolt carrier assembly. AR-15s employ a modular design, thus one upper receiver can quickly and easily be substituted for another. Upper receivers are available with barrels of different weights, lengths, calibers, and rail systems with various sights and accessories. The standard AR-15 rifle uses a 20″ barrel.
The AR-15’s most distinctive ergonomic feature is the carrying handle and rear sight assembly on top of the receiver. As the line of sight is 2.5 in (63.5 mm) over the bore, the AR-15 has an inherent parallax problem. At closer ranges (typically inside 15–20 meters), the shooter must compensate by aiming high to place shots where desired.
The standard AR-15 rifle has a 500 mm (19.75 inches) sight radius, and can also mount a scope on the carrying handle.
The AR-15 is just one of the many weapons that you’ll be able to use in Cold Comfort. You can check out some more firearms here, and the melee weapon overview here.