Automatic firearms having a bolt assisted by an additional mass

An automatic firearm comprising:

• a recoiling bolt,
• an additional mass,
• a stop surface rigidly fastened to a fixed portion of the firearm,
• an amplifying lever having a resting surface directed towards the rear and adapted to come into contact, at the start of the recoil stroke of the bolt, with said stop surface rigidly fastened to a fixed portion of the firearm so as to impart to said amplifying lever a tilting movement having the effect of accelerating said additional mass towards the rear,
• said recoiling bolt being fastened to said additional mass by said amplifying lever, and
• said resting surface and said stop surface having the shape of cylindrical sectors of the same radius of curvature so that the resting surface and the stop surface cooperate by area contact when the recoil movement of the bolt commences when the rearward-directed force applied to the bolt is maximum.

An automatic firearm comprising:

• a recoiling bolt, said bolt having a front resting surface,
• an additional mass,
• a fixed stop surface,
• an amplifying lever pivotally mounted on said bolt by a transverse pivot pin, said amplifying lever having a resting surface adapted to come into contact with said fixed stop surface at the start of the recoil stroke of the bolt,
• said recoiling bolt being fastened to said additional mass by said amplifying lever,
• a bolt box, said bolt box having guide members for said bolt, and
• the relative positions of the front resting surface of the bolt on a cartridge in firing position, of the transverse pivot pin, of the amplifying lever, and of the resting surface by which the amplifying lever cooperates with the fixed stop surface and with the additional mass respectively are such that, at least at the start of the recoil stroke of the bolt, the resultant of the forces produced on the bolt by the cartridge which has just been fired, by the additional mass, and by the fixed stop surface tends to bring the rear portion of the bolt against the guide members, whereby guiding of the bolt is improved and different plays are constantly taken up in the same direction for assuring a constant ratio of amplification of the amplifying lever and therefore uniformity of firing.

An automatic firearm comprising:

• a recoiling bolt,
• an additional mass,
• an amplifying lever,
• said recoiling bolt being fastened to said additional mass by said amplifying lever,
• a fixed stop surface,
• a cage for receiving a clip of the firearm,
• said amplifying lever cooperating with said fixed stop surface at the start of the recoil stroke of the bolt, and
• said amplifying lever and said fixed stop surface being to the rear of the cage so as to decrease frictional forces and for increasing the regularity of operation with the firearm.

An automatic firearm comprising:

• a recoiling bolt,
• an additional mass,
• an amplifying lever,
• said recoiling bolt being fastened to said additional mass by said amplifying lever,
• a cage for receiving a clip of the firearm, and
• resting surfaces to the front and rear respectively of the cage for guiding the bolt at the start of its recoil stroke.

An automatic firerarm comprising:

• a recoiling bolt,
• a firing pin housed in the bolt,
• an additional mass,
• an amplifying lever,
• said recoiling bolt being fastened to said additional mass by said amplifying lever, and
• said amplifying lever being a rear retention stop for the firing pin whereby firing is made impossible if one has forgotten to put the amplifying lever in place.

An automatic firearm comprising:

• a recoiling bolt,
• an additional mass,
• an amplifying lever,
• said recoiling bolt being fastened to said additional means by said amplifying lever,
• said bolt, mass, and lever being a movable unit,
• a barrel,
• a guide rod rigidly connected with the barrel and removably fastened to the additional mass,
• an airtight housing slidably mounted on the guide rod,
• a recoil spring housed in said housing, and
• said movabie unit being biased by said recoil spring whereby said recoil spring need only be lubricated once and said recoil spring can remain on the firearm.

An automatic firearm comprising:

• a recoiling bolt,
• an additional mass,
• an amplifying lever,
• said recoiling bolt being fastened to said additional means by said amplifying lever,
• a recocking rod, said recocking rod having a pivoting hook, said hook having an inclined resting surface, said hook being biased by a spring,
• a barrel,
• a stop rigidly connected with the barrel, said stop having an inclined resting surface, and
• said pivoting hook being adapted to cooperate, at the end of the closing stroke of the additional mass, with said stop, said hook and said stop cooperating by contact between their respective inclined resting surfaces so that said hook remains in a hooked position despite the rebound forces acting on the additional mass upon its arrival into closed position and so that said hook is released from its rest under the effect of the recoil force, which is far greater than the rebound forces, produced by the firing of a cartridge.