An aiming system for attachment to a weapon has a laser for projecting a beam of light onto a target to assist in aiming the weapon. The aiming system permits the laser to be releasably attached to the firearm by providing a mount which is releasably attached to an adapter secured to the aiming system. To protect the laser from severe recoil shock and to provide a rugged housing which prevents accidental damage or undesirable contaminants from damaging the system, the laser is enclosed within the dustproof housing and connected to a bufer means also carried within the housing. The aiming system further permits easy substitution of interchangeable housings, each enclosing a laser, by providing a mount fixed to the weapon which has a bore sighted adjustment mechanism that serves to adjust the position of the laser with respect to the barrel of the weapon. To prevent damage from lateral impact of the aiming device, a lateral shock absorbing material is provided between the laser tube and the housing.