Fig. 6 represents a percussion tube or nipple, through which the fire from the percussion-cap is to be conducted to the chamber. Fig. 7 represents the same in section. The outer end, _h_, of the tube has the opening made as large as convenience will allow, and it goes tapering or conical until at the inner end, _i_, it is as small as a proper entrance of the flame from the percussion-powder will warrant. By giving the conical or funnel-formed opening to the tube the effect of the percussion-powder is greatly increased. E, Figs. 1 and 8, is a bolt for locking the receiver when a loaded chamber is brought to coincide with the barrel, the rounded end _j_ being forced into a hole in the receiver by the action of a spring on its outer end _k_. This bolt is drawn back by the hammer F in the act of cocking. _l_, Figs. 1 and 9, is a spring-cam, which is screwed to the hammer at _m_. It is made of spring-steel, so that its cam end _n_ may recede from or approach the hammer F. The cam _n_ bears against the projection _o_ on the bolt E on the side which lies against the hammer, and as the hammer is drawn back causes the bolt to recede. The bolt is notched to enable it to be withdrawn without interfering with the joint-pin _q_ of the hammer. The lateral springing of the cam-piece _l_ is necessary to admit of its passing by the projection _o_ of the bolt when the hammer is made to strike upon a percussion-cap. To enable the spring-cam to pass the bolt E, the lower end of it, _n_, is made wedge-shaped, diminishing to a point or edge at its extremity, and as it is made to spring laterally it is received into a recess in the hammer as the latter passes the bolt in making the discharge.