Abstract: The disclosure describes a convertible lower receiver. The convertible lower receiver includes a first forward pivot assembly and a second forward pivot assembly. The first forward pivot assembly is associated with a first forward pivot receptacle that is designed to mate with a first type of upper receiver when a forward takedown pin is inserted through the first forward pivot receptacle and a forward lug of the first type of upper receiver. The second forward pivot assembly is associated with a second forward pivot receptacle that is designed to mate with a second type of upper receiver when the forward takedown pin is inserted through the second forward pivot receptacle and a forward lug of the second type of upper receiver.

Abstract: The present invention discloses a firearms safety system for adapting conventional handheld firearms to fire non-deadly simulated training ammunition, which system provides a series of gas relief ports and passages to prevent the successful firing of live ammunition in the firearm. The system can be advantageously utilized in modified M16 type military type rifles which have been previously adapted to fire pistol cartridges such as the 9 mm and .40 S&W calibers.

Abstract: An M16 type rifle capable of being fired in automatic or semi-automatic mode is disclosed utilizing a blow-back system with a forcing cone breech and a matching conical bolt face. The blow-back bolt assembly of the present invention allows elimination of the troublesome and easily fouled gas operating system of the conventional M16 rifle and further allows the rifle to be chambered for short low-pressure pistol cartridges such as the 45 ACP and the 40 S&W.

Abstract: An M16 type rifle capable of being fired in automatic or semiautomatic mode is disclosed utilizing a blow-back system with a forcing cone breech and a matching conical bolt face. The blowback bolt assembly of the present invention allows elimination of the troublesome and easily fouled gas operating system of the conventional M16 rifle and further allows the rifle to be chambered for short low-pressure pistol cartridges such as the 45 ACP and the 40 S&W.

Abstract: A modified M16 pistol capable of firing rifle cartridges therein in automatic or semi-automatic mode, which pistol is based upon modified M16 upper and lower assemblies, with a pistol barrel, an M16 gas actuation system, and a spring-biased buffer system mounted on top of the M16 upper receiver assembly.

Abstract: An M16 type rifle is disclosed having a gas piston assembly with a relatively large piston area and sufficient stroke to actuate the M16 bolt carrier assembly in order to allow the M16 rifle to be chambered for short low-pressure pistol cartridges such as the 45 ACP, 10 mm, and 40 S&W. The gas piston assembly provides relatively constant contact between the piston rod and the gas carrier key of the conventional M16 bolt carrier assembly.