Abstract:
The slide of a pistol using a short recoil locking breech system is internally machined to house a barrel designed to stay in-line during the complete firing cycle. As the slide goes in battery, a mobile bolt is forced upward to lock the handgun and downward to unlock it to let slide and barrel separate after a shot is fixed.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The short recoil locking system is used on most modern center-fire pistols. The most favoured one is still the John Moses Browning tilting, barrel design, either as the original with swinging links of the 1911 Government or the later linkless ramp of the Browning High Power and the numerous models of various makers which followed. On those type of handguns, necessary clearances between the interfacing components and motion of the parts when firing contributes to reduce accuracy. Correction of such problems is possible but requires qualified and expensive gunsmithing. 
       BRIEF SUMMARY 
       [0002]    Basic operating principle of the present invention was exposed in my now abandoned application Ser. No. 12/802,151 filed on Jun. 1, 2010. The invention relates to a short recoil locking system for pistols in which, unlike on the majority of modern handguns of this type the barrel remains in a straight horizontal line during the complete shooting cycle. This system requires less parts of a simpler design increasing inherent accuracy and allowing closer tolerances while limiting stress on the moving parts. Application of the in-line barrel locking technique would take care of the long-standing reliability issues of ultra-short barrel pistols using the tilting barrel locking method. It will also simplify installation of silencers and as the locking assembly is in front of the chamber instead of under it, the barrel can be located deeper in the frame for a lower bore axis to limit apparent recoil and barrel climb in rapid fire. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0003]      FIG. 1  is a left view of a round barrel  1  from a first model kit showing vertical groove  1 . 1  on the chamber front side (groove  1 . 2  being a mirror image on the right side is not illustrated), bottom cut  1 . 3  and bottom lug  1 . 4  which length vary according to the caliber. 
           [0004]      FIG. 2  is a left view of a slide  2  from the first model kit showing the cut-away recoil spring housing  2 . 1 , an open front recoil spring plug  2 . 2  and a short removable bushing  2 . 3 . 
           [0005]      FIG. 3  is a left view of a mobile locking bolt  6  showing ramps  6 . 1 ,  6 . 7  and left wing  6 . 3 . 
           [0006]      FIG. 4  is a rear view of a mobile locking bolt  6  showing the integral lug  6 . 2 , the bottom of ramps  6 . 1  and  6 . 7  and the curved bottom of the lateral wings  63  and  6 . 4 . 
           [0007]      FIG. 5  is a left view of a locking rod/recoil spring guide  8  showing ramps  8 . 2  and  8 . 3 . 
           [0008]      FIG. 6  slows how a locking rod/recoil spring guide  8  is fastened to a 1911 pistol frame. 
           [0009]      FIG. 7  is an upside down view of a slide  2  showing notches  2 . 5  and  2 . 6  for the lateral wings tips of a locking block  6  (the locking block  9  of the second model kits works the same way, its lateral wings  9 . 3  and  9 . 4  entering notches  3 . 5  and  3 . 6  inside the roof of a slide  4 ) and the slide cuts  2 . 7  and  2 . 8  needed to install the locking bolt  6  on the barrel. 
           [0010]      FIG. 8  is a left view of a locking rod  9  showing ramps  9 . 1  and  9 . 7  and left wing  9 . 3 . 
           [0011]      FIG. 9  is a rear view of a locking bolt  9  showing the integral lug  9 . 2 , the bottom ramps  9 . 1 ,  9 . 7  and the lateral wings  9 . 3  and  9 . 4  of the locking bolt  9 . 
           [0012]      FIG. 10  is a partially cut-away left view of a slide  2  showing barrel  1  with an unlocked mobile bolt  6  inside ramps  8 . 3  and  8 . 2  of the locking bolt/recoil spring guide  8 . 
           [0013]      FIG. 11  is a partially cut-away left view of a slide  2  showing barrel  1  with mobile bolt  6  in looked position on top of ramp  8 . 3  of the locking rod/recoil spring guide  8 . 
           [0014]      FIG. 12  is a left view of the slides chamber barrel  3  from a second model kit showing the vertical groove  3 . 1  on front side of the chamber (groove  3 . 2  being a mirror image is not illustrated), bottom cut  3 . 3  and bottom lug  3 . 4 . 
           [0015]      FIG. 13  is a front view of a flat sides slide  4  from the second kit showing the muzzle  3 . 5  of the barrel and the tip  8 . 6  of the recoil spring guide inside the bushingless muzzle end. 
           [0016]      FIG. 14  is a partially cut-away left view of a slide  4  from the second model kit showing how the recoil spring  8 . 1  is installed on the recoil spring guide forepart of a locking rod  8 . 
           [0017]      FIG. 15  is an upper view of an alternate slide  5  showing the top ejector  5 . 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0018]    The present invention refers to short recoil conversion kits made to replace the tilting barrel locking system on different handguns and to build new ones working on the same principle of a barrel remaining in a straight line during the complete shooting cycle. The first model kit, especially designed for .45 caliber 1911 type pistols, has a round barrel with an elongated front chamber ( FIG. 1 ) inserted from the muzzle end of the slide and a short tight fitting removable bushing  2 . 3 . The second kit, adaptable to many different handguns including the 1911 with a longer dust cover in all calibers and a special wide rails frame in .45 has a flat sided slide and barrel chamber and is installed from the bottom of a bushingless slide ( FIG. 13 and 14 ). Kits are made to fit a specific type of handgun without any modification of the original frame except as it is already the case on 1911 pistols when ramped barrels are used. As both kits use the same type of locking rod/recoil spring guide  8  and work on the same locking technique, the first model on a 1911 frame has been chosen to illustrate hereafter the common operating principle of the invention. Slides of the two kits, while differently shaped, have internal channels matching closely the specifications of their respective barrel chambers and inside the roof two rectangular notches,  2 . 5  and  2 . 6  for the first model kit,  3 . 5  and  3 . 6  for the second one, an important part of the locking process. 
         [0019]    To assemble a first model kit on a 1911 frame, a barrel  1  is first set in a slide  2  held upside down and a mobile bolt  6  having an integral lug  6 . 2  ( FIG. 4 ) designed to fit the barrel cut  1 . 3  is placed over it through the slide cuts  2 . 7  and  2 . 8  ( FIG. 7 ) with its lateral wings  6 . 3  and  6 . 4  inside grooves  1 . 1  and  1 . 2  in front part of the barrel chamber. A locking rod/recoil spring guide  8  ( FIG. 5 ) with a recoil spring  8 . 1  on its forepart is positioned in the slide. The slide is fitted on the frame rails and the rod, pushed all the way back inside the original link assembly housing of the frame is fastened to it by the shafts  18  of the slide stop  19  ( FIG. 6 ). The short back and forth movement of the barrel is now limited between the front of the barrel bottom lug  1 . 4  and the flat rear end of the locking ramp  8 . 2 . A bushing  2 . 3  is positioned in unlocked condition inside the slide muzzle and an open front recoil spring plug  2 . 2  placed on the tip of the recoil spring is pressed inside the slide until the bushing can be turned to hold the assembly as on an original 1911 pistol. The pistol is now ready to operate. 
         [0020]    A loaded magazine is inserted and locked in the handgun grip, the slide is retracted and released to move forward under recoil spring force. The first cartridge is chambered, the hammer remains cocked and the slide keeps pushing the barrel for the last fractions of an inch. The lower ramped front base  6 . 7  of the locking bolt  6  bearing on lower opposite front of ramp  8 . 3  ( FIG. 10 ) forces the bolt to slide upward on the top rear part of the ramp  8 . 3  ( FIG. 11 ). Simultaneously, the short forward movement of the slide and barrel stops as the front of the barrel bottom lug  1 . 4  is blocked by the flat rear end of the ramp  8 . 2 . The internal lug  6 . 1  of the locking block has moved up in the barrel bottom cut  1 . 3  and the tips of the lateral wings  6 . 3  and  6 . 4  have entered the internal notches  23  and  2 . 6  of the slide ( FIG. 11 ) locking together slide and barrel. 
         [0021]    After a shot is fired, slide and barrel still joined together recoil for a short distance until the rear end of the barrel bottom lug  1 . 4  bears on the top rear surface of the frame original swinging link assembly housing. Gas pressure still imparting a rearward force on the slide and barrel assembly, the bottom rear angle of the base  6 . 7  from the mobile bolt  6  slides downward on the front angle of the ramp  8 . 2 . At the end of this sequence; the locking bolt  3  is again in the down unlocked position of  FIG. 10  enabling the slide to separate from the barrel and start recoiling to complete the next firing cycle. 
         [0022]    The second model conversion kit represents an improved version of the first one as it requires less parts of a simpler design. Being more economical to produce, it is also easier and faster to assemble. A barrel  3  is inserted muzzle first in a slide  4  held upside down and a mobile bolt  9  is placed over it with its lateral wings  9 . 3  and  9 . 4  inside grooves  3 . 1  and  3 . 2  in front part of the barrel chamber. A locking rod/recoil spring guide  8  with a recoil spring  8 . 1  on its forepart is installed from the bottom of the slide ( FIG. 14 ) and the slide fitted to the pistol frame rails. Depending if the handgun type, this assembly is fastened to the frame either by a slide stop like on 1911 or CZ 75 handguns or a pivoting take-down lever on Sig Sauer or Smith &amp; Wesson MP models and the pistol is ready to operate.