Abstract: A break open sporting firearm with one to four barrels that lock up in line directly behind the chambers for strength and rigidity.The load from firing is taken up by two or more circularly spaced lugs in the breech engaging with mating lugs on the frame.A rotating breech plate slider and hinge within the breech are the functioning means for this invention.

Abstract: A gun conversion assembly for application to the receiver of an automatic pistol having a handle containing a recess into which a magazine holding a series of rounds of ammunition is insertible, the conversion assembly including a barrel to be secured to the receiver, and a connector structure having a portion which is adapted to be located within the magazine recess in the receiver handle and which acts to secure the barrel rigidly to the receiver. The connector structure may extend downwardly through the recess to the bottom of the receiver handle and have elements at the lower end of the handle tightenable to progressively pull the receiver downwardly into tightly contacting engagement with the upper end of the receiver.

Abstract: A gun conversion assembly for application to the receiver of an automatic pistol having a handle containing a recess into which a magazine holding a series of rounds of ammunition is insertible, the conversion assembly including a barrel to be secured to the receiver, and a connector structure having a portion which is adapted to be located within the magazine recess in the receiver handle and which acts to secure the barrel rigidly to the receiver. The connector structure may extend downwardly through the recess to the bottom of the receiver handle and have elements at the lower end of the handle tightenable to progressively pull the receiver downwardly into tightly contacting engagement with the upper end of the receiver.