Fire Control Group AMD 65. The hammer face and top were reprofiled to reduce force needed during recoil to recock hammer. Lots of experimental welding and grinding. A reduced force hammer spring was made using 0.045” diameter music wire bent to the stock configuration but with only one leg.
Bolt Stock AK74
Bolt Carrier It is from an AK74 with 1 inch of length removed from just behind the piston threads. The carrier was welded back together using a brass rod inserted to align the pieces before welding. The carrier and piston assembly was shortened because I moved the gas port closer to the chamber to tap into higher gas pressure. The photo shows it compared to a standard bolt carrier.
Gas Piston Custom made stainless steel one inch in length (not counting threads) The clearance between the gas piston and gas block is about 0.005 inches.
Recoil Spring During testing, an inch at a time was removed from the recoil spring until three inches was removed to reduce the force exerted on the bolt carrier. The metal loops that retain the spring were shortened to reduce the overall length of the assembly and fit it to the shortened bolt carrier.
Gas Tube Custom machined tube with the locking ring from an AMD 65 gas tube spot welded on. The majority of the tube interior diameter is for the large diameter of the bolt carrier. An interior taper is machined on the front end to guide the gas piston to the gas block. The gas block vent holes are only partially obscured.
Front Trunnion An AMD 65 trunnion was cut to fit the mag well up close to the barrel throat. (The photos show the cutting and fitting) Cuts were made using a 4” thin abrasive disk on a hand held grinder. A stream of water was used to keep the trunnion cool and maintain the trunnion’s heat treatment. The cuts did not go up into the locking lugs. The bullet guide was removed and ground so that the AK74 bolt could rotate up the left side. ( The AK74 bolt head has a greater distance from the back of the locking lug to the front of the head than the AK47.) The guide was riveted back into place and later tack welded when the cuts to fit the mag well cut into the rivet area.