A pistol comprising: - a pistol fore-end; - a barrel, supported by the pistol fore-end, which proximally has a combustion chamber extending along a longitudinal axis; - a slide, translatable longitudinally with respect to the pistol fore-end between an advanced configuration in which it closes the combustion chamber, and a retracted configuration in which it is distanced from the barrel to open said chamber, the orientation of the combustion chamber in the advanced configuration and in the retracted configuration being substantially parallel to said axis, said slide having a first locking seat, at least a second locking seat, a first longitudinal grooving and at least a second longitudinal grooving; - a closing organ shaped as a semi-annular block that is rotatable around said axis between a first and a second angular position, said closing organ being solidly constrained in translation to the barrel by a plurality of abutment projections (24, 26) of said barrel, axially spaced, delimiting a seat for slidable housing of the closing organ; - at least one element for drawing in rotation the closing organ, said element for drawing in rotation being fixed to the fore-end, said closing organ having a first locking relief, at least a second locking relief and at least one cam for taking the rotation over from said at least one element for drawing in rotation, said closing organ, in the advanced configuration of the slide, being in said first angular position in which said first and respectively second locking relief (12, 14) engage said first and respectively second locking seat (16, 18) so as to make the barrel and the slide solidly constrained to one another, said closing organ, in the retracted configuration of the slide, being in said second angular position in which said first and respectively second locking relief (12, 14) disengage from said first and respectively second locking seat (16, 18) and slide along said first and respectively second longitudinal grooving (20, 22) present internally on opposite longitudinal walls (62, 64) of the slide so as to enable a balanced and reproducible retraction movement of the slide with respect to the barrel. - a pistol fore-end; - a barrel, supported by the pistol fore-end, which proximally has a combustion chamber extending along a longitudinal axis; - a slide, translatable longitudinally with respect to the pistol fore-end between an advanced configuration in which it closes the combustion chamber, and a retracted configuration in which it is distanced from the barrel to open said chamber, the orientation of the combustion chamber in the advanced configuration and in the retracted configuration being substantially parallel to said axis, said slide having a first locking seat, at least a second locking seat, a first longitudinal grooving and at least a second longitudinal grooving; - a closing organ shaped as a semi-annular block that is rotatable around said axis between a first and a second angular position, said closing organ being solidly constrained in translation to the barrel by a plurality of abutment projections (24, 26) of said barrel, axially spaced, delimiting a seat for slidable housing of the closing organ; - at least one element for drawing in rotation the closing organ, said element for drawing in rotation being fixed to the fore-end, said closing organ having a first locking relief, at least a second locking relief and at least one cam for taking the rotation over from said at least one element for drawing in rotation, said closing organ, in the advanced configuration of the slide, being in said first angular position in which said first and respectively second locking relief (12, 14) engage said first and respectively second locking seat (16, 18) so as to make the barrel and the slide solidly constrained to one another, said closing organ, in the retracted configuration of the slide, being in said second angular position in which said first and respectively second locking relief (12, 14) disengage from said first and respectively second locking seat (16, 18) and slide along said first and respectively second longitudinal grooving (20, 22) present internally on opposite longitudinal walls (62, 64) of the slide so as to enable a balanced and reproducible retraction movement of the slide with respect to the barrel.