This disclosure relates to weapon receivers, profile rails, and weapons. According to one example, a receiver for a self-loading firearm, includes a first guide track within which a loading lever can be moved to move a loading tube that can be brought into contact with, or is in contact with a breechblock; a second guide track connected to the first guide track, wherein the loading lever can be shifted to the second guide track via a first opening in the receiver to move the loading tube, such that the loading lever can be operated ambidextrously. Other examples are contemplated.