Handguard for clamping mounting on an existing firearm

A handguard for mounting on a barrel or a barrel nut of an existing firearm, where the barrel or barrel nut has an annular groove, the handguard comprising:

• a handguard housing having a housing axis, the handguard housing defining a slit running radially thereto, and further defining a through-opening running in a transverse direction, where the through-opening is a long hole having an outline comprised of two semicircles with a first axis and a second axis parallel to the first axis, with a rectangle located in-between;
• and
• a clamping device for mounting in the through-opening of the handguard housing, the clamping device having a lever that defines a lever axis and that includes:
• a center element having a recess in a center area of the center element, the center element extending along and surrounding the lever axis and having a threaded section at a first end portion and a lever arm at a second end portion, where a conical shaft section is provided at the second end portion that widens towards the lever arm and is configured to contact a corresponding conical clamping surface of the handguard housing;
• and
• a nut having an internal thread that matches the threaded section of the first end portion of the center element;
• such that when the handguard is in its assembled state, the lever is disposed in the through-opening of the handguard housing in a plane normal to the handguard axis, the nut is screwed onto the threaded section thereby narrowing the slit, and an angular position of the lever about the lever axis is such that the center element contacts the annular groove of the barrel or barrel nut.