Recoil gas system for rifle

In an original automatic weapon which has an upper receiver interiorly housing an original bolt carrier which carries a bolt which chambers a round of ammunition for firing and which ejects a spent casing after firing;

• said original bolt carrier having auto-firing timing edge for actuating an original trip sear housed partially in a lower receiver of said weapon;
• a barrel down which a projectile and its propelling gasses travel;
• a vent for venting a portion of said propelling gasses from said barrel;
• a gas tube for communicating said portion of propelling gasses from said vent to a carrier key on said original bolt carrier, said gasses passing through said carrier key and driving said original bolt carrier against the restraint of an original recoil spring;
• an original buttstock affixed to said upper receiver;
• whereby a spent casing is ejected and a new round is chambered, said gasses carrying heat, powder residues and dirt into said original bolt carrier and said upper receiver;
• the improvement modifying said original weapon wherein said carrier and said upper receiver are isolated and maintained free of said heat, powder residues and dirt carried by said gasses, said modifying improvement comprising:
• a rod having a first end integrally coupled to said carrier key and inhibiting passage of said gasses into and through said carrier key and bolt carrier, the integral coupling of said rod and said carrier key preventing any impact shock between said rod and said carrier key;
• said rod having a second end inserted into said gas tube;
• a piston affixed to said second end of said rod and driven by said gasses to traverse said gas tube, driving said rod, in turn, to move said carrier key and said bolt carrier against said recoil spring to cause the ejection of a spent casing and the chambering of a new round,
• a substitute recoil spring mounted on said piston rod to be stressed by movement of said piston driven by said gasses,
• said substitute recoil spring being a replacement for said original recoil spring which was originally housed in said buttstock,
• said substitute recoil spring being the means for returning said piston, and said bolt carrier and causing the chambering of a new round, and
• a substitute, replacement bolt carrier having a length selectedly reduced with respect to the length of said original bolt carrier of said original weapon whereby rearward displacement of said substitute, replacement bolt carrier is restricted to the interior of said upper receiver of said weapon.

An improved gas driven automatic weapon produced from the original weapon by the process of:

• integrally coupling a first end of a piston rod to the carrier key of said original weapon so that said rod and said carrier key move together free of relative motion between them;
• affixing a piston to a second end of said piston rod;
• inserting said piston and piston rod into a gas tube mounted on the barrel of said original weapon, said gas tube being coupled to a vent in said barrel for venting projectile propulsion gasses from said barrel into said gas tube;
• using said gasses, vented into said gas tube to drive said piston along said gas tube to drive, in turn, said piston rod and said carrier key so as to move the bolt carrier of said original weapon to the rear of said weapon;
• providing means for variably adjusting the volume of said gas tube;
• and
• setting said means for variably adjusting said volume of said gas tube to selectedly increase and decrease said volume, whereby the automatic rate of first of said original weapon is selectedly decreased and increased;
• and further
• providing a substitute, replacement bolt carrier mounted on said piston rod and having a length selectedly reduced with respect to the length of the original bolt carrier of said original weapon whereby the rearward displacement of said substitute, replacement bolt carrier receiver is selectedly reduced relative to that of said original bolt carrier,
• said substitute, replacement bolt carrier replacing said original bolt carrier originally carrying said bolt for chambering said round.

An improved gas driven automatic weapon produced from the original weapon by the process of;

• coupling a first end of a piston rod to the original carrier key of said original weapon;
• affixing a piston to a second end of said piston rod;
• inserting said piston and piston rod into a gas tube;
• mounting said gas tube on the barrel of said original weapon
• coupling said gas tube to an original vent in said barrel for venting projectile propulsion gasses from said barrel into said gas tube;
• using said gasses, vented into said gas tube, to drive said piston rod along said gas tube to drive, in turn, said piston rod and said carrier key toward the rear of said weapon;
• removing the original buttstock-housed recoil spring from said original weapon.
• providing a substitute recoil spring and mounting it on said piston rod;
• housing said substitute recoil spring in said gas tube to be stressed by said piston when said gasses drive said piston along said tube, said substituted recoil spring thereafter returning said piston, and piston rod to their forward positions in said original weapon;
• removing the original bolt carrier from said original weapon;
• and
• replacing said original bolt carrier with a substitute, replacement bolt carrier having a length selectedly reduced with respect to the length of said original bolt carrier so that the rearward displacement of said substitute, replacement carrier is selectedly reduced relative to that of said original bolt carrier.