Section 6: Reassembly
At this point you should have the completed receiver and these parts:
All that is left to do is press in the barrel, install the FCG and put on the furniture. At that point you will need to go to the range and test fire for function. All of the builds I have done have required some form of "Tweaking" to run properly. This is also the point you will want to decide what US parts you are going to install for compliance. I will be using a TAPCO G2 trigger, hammer and sear, a US made pistol grip and a US made muzzle brake.
You will need the following tools: You will need the following materials:
3 lb hammer High pressure grease
Bench vise 2 x 7/32 "E" clips
The ram you made to remove the barrel
Large punch
Needle nose pliers
Large and small screw driver
Round file
The first thing to do is coat the inside of the front trunnion with the high pressure grease. I use RCBS case lube since it is designed for this type of application. Start the barrel into the trunnion by hand. You can index it by lining up the rear sight with the ears on the front trunnion. Make sure that the barrel is started true to the trunnion and in line with the top of the receiver.
Open the vise up so that the front of the rear sight block can rest on it and everything else is free. Using you ram on the top of the rear trunnion only start pounding the barrel home.
As the barrel is seating keep an eye on the barrel pin slot. This must be lined up correctly to maintain headspace. As it gets close check it after every hit. Once it is lined up the barrel is back in. You can replace the barrel pin from the right side and seat it using the large punch.
Next install the furniture.
Now is the time to check the headspace. If you do not have access to headspace gauges I would recommend that you have it checked by a gunsmith. If you do have the gauges here is how to do it. Strip the firing pin and extractor from the bolt and try to close it on the No Go gauge. If it will not close even with light pressure recheck it with the Go gauge. If it will close on the Go gauge the headspace should be OK. If it closes on the No Go gauge I would have it checked by a gunsmith as the headspace may need to be reset.
Next you will install the FCG and selector. Check the pivot pin holes to ensure that the pins will seat properly. If not, use the round file to correct the issue. Start with the hammer and main spring. The hammer and spring are installed as shown. Start by setting them in sideways and then rotating them so the pegs on the back end of the spring arm are pointing down. Rest the hammer on top of the center support and insert a pivot pin through it from the left and seat the pin in the right side of the receiver. Lock the pin in place with an "E" clip on the left side.
Next install the safety selector from the right side. Line up the selector arm with the matching hole on the left side of the receiver. Rotate the selector forward and down until it stops. Now you will set the trigger/sear assembly in place. If you are using a US made set you can assemble the trigger, sear and sear spring outside the rifle and drop them in. Be sure to install the sear spring between the trigger and sear. This is a common error that comes up on the boards often. If you are using the original FCG you will put the trigger in first and then lower the sear and spring on to it and lock it in place with the pivot pin. Be sure that the pivot pin is under the main spring arms on both sides. Hook the main spring arms over the back of the trigger and secure the pin with an "E" clip.
Now cock the hammer back so it catches on the front hooks of the trigger. Rotate the safety selector up until it is parallel with the top of the receiver and check that the trigger can not be pulled to release the hammer. If the trigger does release the hammer you will need to extend the safety selector base by welding it and shaping with a file. With the safety in the down "Fire" position and the hammer engaged with the trigger install the bolt and carrier, recoil spring and dust cover.
You should now have something that looks like this!
Congratulations! You have competed your AK build. There are still a few things that need to be done like test firing and fine tuning. When you go to the range take a couple of files and some WD40. The rifle will need a little brake in time and some lubricant will help. Please take proper precautions during the test firing.
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