Install the clutch spring. First, insert the magazine catch spring on the left side of the lower receiver. You will know the left side of the receiver because it has all the writing on it. Then from the right side of the lower receiver install the magazine catch spring. Last, push the magazine catch button towards the magazine catch, and spin to tighten. Spin until the magazine catch is flush or nearly flush with the button.;
, Before you start, use some masking tape to cover the lower receiver just to the right of where you install the bolt catch. This masking tape will prevent scratches when you tap in the bolt catch roll pin.


First, insert the roll pin and tap it in part way. Second, insert the bolt catch spring and buffer. When you do this the spring should face in, and the buffer out. Now you are ready to install the bolt catch.
Hold the spring tension on the plunger, and align the hole in the bolt release with the roll pinhole in the lower receiver. Use a punch to tap the pin all the way in. Alternatively you could use a pair of pliers and press the pin in.
If your bolt catch is sticky after installation there is a problem. The hole in the bolt catch should be large enough that the bolt catch release pin can pass through. If you have this problem, you can do one of two things:

Call your vendor and get a replacement part.
Ream out the hole with a tiny drill, or grind it with a Dremel or very small round needle file.
 First, insert the spring in the detent hole, next insert the detent. Note that you will need to force the detent in against the spring. While the detent is in, use the pivot pin to hold the detent back down in its hole against the spring, as you insert the pivot pin in its hole in the lower receiver. When in, the pivot pin will hold the detent in place.
 Slip the trigger guard between the support ears on your receiver. Gently tap the roll pin in place. Be careful that the hole in the trigger guard stays aligned with the holes in the two ears on the receiver, as you tap in the pin. If the holes are misaligned you will bend your pin.
 Drop the trigger and the trigger spring assembly into the lower receiver. Push the disconnector over the coil spring. Then insert a trigger pin through the lower receiver, through the disconnector, and to the other side of the receiver. You may have to wiggle it a little, but it will go.
 Insert the hammer and hammer spring assembly into the lower receiver. The two long legs of the hammer spring will rest on the top of the pin installed in the "Install the trigger" step. Push the hammer into the receiver until the holes in the hammer line up with the holes in the receiver. Then lightly tap the pins in. Cock the hammer.


Note that the hammer is under tension, so you will have to push/squeeze the hammer in to get the pin holes to line up.
 To install the safety selector, place the selector detent and the spring into the detent hole.
 When installing the pistol grip make sure that the selector spring goes into the hole in the grip.
 Install the detent and the spring, then install the pin in the rear of the receiver. Note that this rear pin will be held in place when you install the stock in the next step.
 Thread the rifle/carbine buffer tube into the receiver. Do this slowly and carefully, thread until just to the buffer hole. Then insert the buffer pin and buffer spring into the buffer stop. After the buffer pin and spring is in, thread some more. Go until the rifle/carbine tube holds the rear takedown pin in place. Note, the rifle/carbine tube should hold the pin in place but it should not touch the center of the pin and bind the pin's movement.


Whether you have a CAR nut or a castle nut, you can use a CAR wrench to tighten the stock.
You may choose to add a drop or two of loctite to the threads of the nut before tightening. This is optional, and if you plan on disassemble soon, you may choose not to do this.
 Cock the hammer; insert the spring, and then the buffer. Push the buffer in past the buffer pin.
 Perform a trigger mechanism check as follows :


Verify that hammer locks to the rear when pushed back.
Verify that hammer pivots forward when trigger is pressed.
Without releasing the trigger, push the hammer back again and verify that it locks (caught by disconnector).
Releasing the trigger should not cause the hammer to pivot fully forward (caught by trigger).
Hammer will fall when trigger is pressed.
 Your lower receiver is now complete or assembled, and ready for an assembled upper receiver.


It is important, that you do not "dry fire" your completed lower receiver by itself. Doing so may damage the lower. Wait until you have assembled your lower receiver with your upper receiver. Only then, when your firearm is fully assembled is dry firing okay.
Install the catch spring.
Install the bolt catch.
Install the detent.
Install the trigger guard.
Install the trigger.
Install the hammer.
Install the safety selector .
Install the pistol grip and grip screw .
Install rear takedown pin.
Install the stock .
Insert the carbine/rifle buffer and spring .
Check the function.
Lower receiver is now complete.
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