254 APPENDIX. 



Sight-Plate. — See Top-Piece. 



Spring-Cramp. — An instrument for taking out the main- 

 spring. 



Stock. — The wooden part of the gun, which supports 

 the barrel, and comes to the shoulder in shooting. 



Striker. — See Cock. 



Swivel. — See Chain. 



Top-Piece, Sight-Plate, or Upper-Rib.— The elevated 

 metal plate along which the eye is directed to the sight. 



Triggers. — Light pieces of metal, protected by the 

 guard, and extending to the interior of the lock, which, 

 upon being pressed by the finger, withdraw the scear 

 from the tumbler, and thus permit the cock to fall and 

 explode the cap. 



Trigger-Plate. — The plate in which the trigger works. 



Trigger-Spring. — The small spring that, pressing 

 against the trigger, keeps it close to the scear. 



Tube. — See Nipple. 



Tumbler. — The movable centre-piece of a lock, hav- 

 ing an axle passing through the lock-plate to which the 

 cock is fastened. 



Tumbler-Screw or Pin. — The screw with which the 

 cock or hammer is fastened to the tumbler. 



Under-Cross Pin. — The screw which passes through 

 the front of the guard or trigger-plate into the base of the 

 break-off. 



Under-Rib. — The piece of metal running the whole 

 length of the barrels, which, together with the upper rib 

 or sight-plate, holds them securely together. 



Vent or Vent-Hole. — A small hole at the side of the 

 breeching, intended to allow the escape of a portion of the 

 explosive force, and lessen the recoil. 



