Abstract: Breechblock with firing pin for mortars, which has barrel (1), breechblock (2), and base plate (3) united as follows:(a) barrel (1) to breechblock (2), using at least one key (8) accomodated in key seat (11) of barrel (1) and provided with holes (81) into which pins (8) are inserted; and at least one screw (7) accomodated in a threaded hole (21) of breechblock (2), said screw (7) defining two coaxial zones in its body, one of greater diameter of external treading (71) which is attached in breechblock (2), and another of smaller diameter provided with perimetral neck (72) in which pins (9) positioning key (8) are accomodated;(b) breechblock (2) to base plate (3) with possibility of turning in space, using positioning head (26) in the end of breechblock (2); support flange (4) over platform base (3); cover rib (5) attached by screw (20) over support flange (4) and which holds rib (6) in it, into which said head (26) of breechblock (2) runs.

Abstract: The improved mortar has a sealing means that provides a double seal to the firing pin so that hot ignition gases from the mortar tube are prevented from damaging the firing mechanism. The improved mortar also has an improved base plate, the improvement in the base plate being an even number of radial ridges that extend radially from the base plate and are arranged in equal angles at the center. Every other radial ridge is forked and the branches of the forked radial ridges are parallel to the adjacent non-forked radial ridges.

Abstract: A mortar shell time fuse of the type which consists of a body and a head, and characterized because it is comprised of:(a) a secondary mass floating upon a return spring in a hole in the body;(b) means for holding the secondary mass at rest;(c) a gear train subjected to the action of a torsion spring and linked at rest with the secondary mass, and comprised of:(c.sub.1) means of retarding its rotation.(c.sub.2) means for the restraining and releasing of:(d) a shell holder with a rotation shaft subject to the action of a torsion spring.

Abstract: Shell for firing practice comprised of a master projectile in the form of a conventional shell which has a hole along its entire axis for the purpose of inserting inside a small bore projectile that comprises a sleeve and in whose inside there is concentrically placed in axial continuity, a cartridge positioned on the bottom of the sleeve which has a first explosive charge that is activated by the mortar firing pin, and where said cartridge possesses a wad having at least one hole to allow the expansive wave to be transmitted to a second firing pin which activates a second explosive charge, and means for transmitting the impelling action of said second charge to a carried projectile.