The present invention is a sling system utilizing a rear sling fitting for a long firearm, such as a rifle. Such fittings typically are positioned between the stock and receiver. It presents a fitting body with an aperture to slide over a rifle receiver tube and a connection bar extending from a reverse of the fitting body. A point-type sling attachment may then be attached to the connection bar and be able to slide left and right across the back of the weapon, allowing for quickly adaptable left or right positioning of the weapon. Registration geometry may be added and positioned to further allow interface with weapon geometry and prevent rotation of the fitting during use. The connection bar may be positioned on another component of the weapon, such as the receiver or the stock, should the weapon not have a receiver extension tube. A convertible sling and forward sling mount are also disclosed for cooperative use with the fitting, completing the system.