Abstract: An improved gun design is disclosed which includes a highly effective and accurate hammer rebounding mechanism and a safe and efficient locking mechanism for securing the barrel of a breech load gun to the frame. Particularly, the rebounding mechanism encompasses a torsion spring device which controls the hammer of the pistol to effectuate an automatic hammer rebound after firing. There is also included a procedure to assure proper rotation of the hammer and a procedure to maintain the hammer in its rebounded position when the gun is at rest. The locking mechanism of the present invention increases the ease and speed with which the barrel can be moved into a loading position. Another feature of this locking lever is that if excessive force is applied to the locking lever in an attempt to unlock the barrel from the frame, an accidental discharge from a fully cocked hammer will be prevented.