Barrel holder for a drop-down barrel weapon

1. Barrel holder for a drop-down barrel weapon comprising:

at least one tapped hole, an interchangeable barrel including a corresponding thread to screw into the tapped hole, the barrel holder further including a ring shoulder receiving space between the tapped hole and a cartridge insertion end of the barrel holder for receiving a ring shoulder adapted to support an edge of a cartridge, and a circumferential ring shoulder positioned in the ring shoulder receiving space;

wherein the circumferential ring shoulder comprises a first arc section and a second arc section, the first arc section being formed from an interchangeable, axially movable cartridge extractor positioned in a retracted position, the axially movable cartridge extractor being movable between the retracted position and an extended position, the circumferential ring shoulder corresponding to the caliber of the interchangeable barrel, and the second arc section of the ring shoulder being formed by an interchangeable adapter part corresponding to the caliber of the interchangeable barrel, the interchangeable adapter part being sandwiched between the interchangeable barrel and a shoulder formed in the cartridge insertion end of the barrel holder,

wherein the interchangeable adapter part comprises an inner curved surface shaped and sized to abut a portion of an outermost diameter of an edge of a cartridge to be accommodated in the interchangeable barrel, the adapter part being a separate removable and replaceable component part from the interchangeable barrel, and

wherein the axially movable cartridge extractor has an inner curved surface having the same radius of curvature as the inner curved surface of the adapter part and sized to abut a remaining portion of an outermost diameter of an edge of a cartridge to be accommodated in the interchangeable barrel.

2. Barrel holder according to claim 1 , wherein the adapter part further includes an axial section, the inside curvature of which corresponds to the inside diameter of the interchangeable barrel to be accommodated.

3. A weapon comprising:

a barrel holder having at least one tapped hole for receiving an interchangeable barrel and a ring shoulder receiving space for receiving a ring shoulder adapted to support an edge of a cartridge, the ring shoulder receiving space being positioned between the tapped hole and a cartridge receiving end of the barrel holder, the ring shoulder receiving space of the barrel holder including a tiered groove, the barrel holder further comprising a circumferential ring shoulder positioned in the receiving space and adapted to support an edge of a cartridge corresponding to the caliber of the interchangeable barrel, wherein the ring shoulder comprises an interchangeable adapter part inserted into the ring shoulder receiving space of the barrel holder and forming less than a circumferential whole of the ring shoulder, the adapter part being a component separate from the interchangeable barrel and forming a first arc section of the circumferential ring shoulder, the adapter part having an inner curved surface shaped and sized to abut a portion of an outermost diameter of an edge of a cartridge to be accommodated in the barrel, the remainder of the ring shoulder being formed by an interchangeable cartridge extractor positioned in a retracted position, wherein the cartridge extractor is configured to be moved axially with respect to the barrel holder between the retracted position and an extended position, and further wherein the adapter part includes a shoulder fitted into the tiered groove of the barrel holder and is secured in place by being sandwiched between the interchangeable barrel and the tiered groove.

4. A weapon according to claim 3 , wherein the adapter part further includes an axial section having an inside surface with a curvature corresponding to the inside diameter of the interchangeable barrel.

5. A weapon comprising the barrel holder of claim 1 .