[FightinTexasAggie]

I am finally finishing my first AR build (and first AR) I ran out of funds for a while back. Im pretty sure I have everything ordered that I will need to complete the rifle, and wanted the experts to give me feedback. I decided to go with a complete upper to avoid buying more expensive tools.

CMMG Stripped Lower Receiver
Del-Ton Complete Lower Parts Kit
M4 CAR Buttstock Assembly - With Buffer and Spring
Yankee Hill Machine - Black Diamond Specter XL Top End

Do I have everything I will need to complete my AR (not counting tools)?

[mjkeat]

It didnt look like the stock kit came with a buffer plate. Its the plate that goes on the end of the lower and is held in place by the castle nut. It holds the rear take down pin detent spring in place.

[FightinTexasAggie]

I got the parts in yesterday, and it did come with the plate. I have 2 more questions for now.

What needs to be oiled/lubricated as I put everything together?
What do I need to do to function test it before any live rounds see the rifle?

[Dillinger]

For just the lower, or for the complete rifle?

The lower is going to require very little in the way of grease or oil to start with. A very thin wiping down at the most just to protect against the oils from your hands.

DO NOT - and I can not say this enough - DO NOT:

Assemble the lower, cock the hammer and pull the trigger allowing the hammer to slam forward into the front half of the lower receiver!

NEVER, NEVER, NEVER, NEVER, NEVER, NEVER, NEVER, NEVER, NEVER, NEVER, NEVER, NEVER, NEVER, NEVER, NEVER Do that.

[Sniper03]

Fightin,

Since you purchased the complete Upper & Barrel Assembly together you do not need anything but a good weapon lube like G-96, Breakfree (Of course shake it up first). As Dillinger advised just lube the entire weapon with a light coat and wipe the excess off. All of your parts being new have little if any lube on them. Put a drop of oil (Lube on the spring coils of both the Hammer and Trigger. Lube your Bolt Carrier Group well before you start shooting. I like them looking a little wet. Then you can do a few break in shots and enjoy! If you would have put the barrel on the upper then you would have needed to use a High Temp Anti Seize grease on the threads of the receiver before putting the barrel nut in place. One other word of caution. Be sure when you installed the Stock Extension Tube into the lower Receiver that the engagement of the Extension Tube is approximately engaged 1/2 way between the little tip of the Buffer Retainer and the outside edge of the Buffer Retainer. And of course the Castle Nut is tight and will not come loose.
If not you can actually tear up a receiver if it does not have proper location engagement and the Buffer Retainer starts coming out of the receiver.
Good luck with the new rifle! Sounds great!

03

[FightinTexasAggie]

I took the stock in to a local shop that does a lot of work on ARs instead of buying the tool. It looks like they tightened the buffer tube right against the piece on the retainer, but it is not blocking the retainer from moving at all.

I'm kind of confused as to how the trigger/hammer/disconnecter work. The trigger will barely move unless the hammer is down. Might be normal, but what pulls the hammer down every time you pull the trigger? The disconnecter also will barely move. I checked a few guides and can't see anything I might have done wrong.

[Sniper03]

Fightin,

The closer the extension tube (Stock Tube) is to that tip and still does not inhibit the Buffer Retainer the better it is. Sounds like they did a good job.
As far as the issue with the Disconector. It may be? That you have the Disconector Spring in upside down. The spring has a larger coil on one end and a smaller coil on the other. The Large Coil goes down into the Trigger recess first and snaps in there so it will not fall out. The small coil is at the top and goes in the window on the Disconector. If you have it upside down the larger coil is at the top and when you push down on the Disconector the large coil hangs on the top edge of the trigger. Check that out and let me know if I can be of any assistance.

03

[FightinTexasAggie]

The disconnecter spring is in right. I may have everything right, I'm just not real familiar with how everything is supposed to work. I probably will take it in tomorrow and let the experts go through and check it out just to be safe.

[Sniper03]

Fightin

Do you know how to do a function check on it. If it does that correctly you are OK. If you do not I will advise you. What happens is when the trigger is pulled and the weapon is fired, since in theory the rifle is cycling at around 700 rounds a minute as far as mechanics speed. Since it happens so quickly you could not get your finger off of the trigger that fast and the hammer would just follow the Bolt Carrier forward and probably would not fire. The Disconector grabs the hammer lets the hammer spring maintain tension and the Bolt Carrier goes into battery. When the operator lets go and the trigger goes forward the Hammer is transferred to the sear and the front portion of the trigger. If you attempt to do this with your fingers you have a tendency to force down farther which causes over travel and it does not seem to work correctly.

[mjkeat]

Go here and check out the videos just below the top right corner.

Just checked my factory LWRC and the trigger has play with the hammer forward and with the hammer locked. When locked the hammer will draw in slightly when working the trigger. As long as the hammer doesnt drop with the safety on and it passed a functions check you should be good.