THE LOCK. 



239 



Fiq.SJ. 



MAINSPRING AND SWIVEL. 

 (HALF SIZE.) 



a peculiar shape lying be- 

 tween the plate and the bridle, 

 and acted on through the swivel 

 (fig. 31, a), by means of the 

 mainspring (fig. 31, be), which 

 is attached to the plate in its 

 upper half. It will be seen on 

 examination, that by the pecu- 

 liar form of the tumbler and 

 swivel, the lever upon which the spring acts is longer when 

 the striker is down on the nipple than at full or half-cock, 

 and thus it exerts its greatest force in that position. In the 

 back of the tumbler (6) are two notches or " bents," one deeper 

 than the other, which are intended to receive the scear. This 

 and its spring (fig. 32) are both attached to the bridle, lying 

 between it and the plate, and working upon two screws, 

 which pierce them. The scear has a sharp tooth which 

 drops into the notches of the tumbler one j^ 32 

 after the other, and is kept there by the 

 spring. When the scear is dropped into 

 the half-cock bent, this is so deep that it 

 cannot be depressed out of it by raising the 

 other end by means of the trigger, and consequently the gun 

 cannot be fired in that position. But at full cock the notch 

 is much shallower, and a force usually equal to about 3 or 

 41bs. will disengage it when applied to the trigger. The 

 side nail is the screw which attaches the lock to the stock, 

 through the hole drilled in the plate in front of the cock. 

 This lock may therefore be considered as consisting of four 

 important divisions : (a) the skeleton or plate and bridle; 

 (6) the cock and tumbler; (c) the mainspring and swivel; 

 and (d) the scear and scrar spring. 



(a.) Tlie shape ofthejjlateh'as three chief variations one the 

 fore-actioned bar-] date, being that which is engraved above, 

 and which is now generally used for best guns ; the front part 

 being accurately iitted to the barrel. In the old plan there 

 was a thin layer of the stock intervening, which was apt to 

 be splintered ; but this is only now used for cheap guns, 

 in which the wood is made to cover bad workmanship. 

 The back-actioned lock, as shown in the Lefaucheaux gun 



