Abstract: Aspects described herein relate to an ammunition round for an open chamber gun mechanism is provided, the round comprising a housing having a triangular shaped cross section and a central longitudinal axis, the housing including at least one projectile positioned along the central longitudinal axis, a propellant positioned behind the at least one projectile along the central longitudinal axis, a first sealed end located at a first end of the housing nearest the propellant, and a second sealed end positioned at a second end of the housing in front of the projectile, wherein the second sealed end is configured to become unsealed after firing of the projectile.

Abstract: Aspects described herein relate to an open chamber gun mechanism comprising a frame and a cylinder assembly that forms an open chamber positioned for rotation within the frame, said open chamber including an insert positioned within the open chamber, the insert forming an expandable region between the open chamber and cylinder. According to one embodiment, the insert is configured to deflect into the expandable region upon firing the open chamber gun mechanism.

Abstract: Aspects described herein relate to an ammunition round for an open chamber gun mechanism is provided, the round comprising a housing having a triangular shaped cross section and a central longitudinal axis, the housing including at least one projectile positioned along the central longitudinal axis, a propellant positioned behind the at least one projectile along the central longitudinal axis, a first sealed end located at a first end of the housing nearest the propellant, and a second sealed end positioned at a second end of the housing in front of the projectile, wherein the second sealed end is configured to become unsealed after firing of the projectile.

Abstract: Aspects described herein relate to an open chamber gun mechanism comprising a frame and a cylinder assembly that forms an open chamber positioned for rotation within the frame, said open chamber including an insert positioned within the open chamber, the insert forming an expandable region between the open chamber and cylinder. According to one embodiment, the insert is configured to deflect into the expandable region upon firing the open chamber gun mechanism.