AR-15 Build Part 9

In B.O. Special, I introduced the newest addition to the gun cabinet and reviewed the rifle kit from Del-ton.
In Part 1, we talked about tools and preparation and installed the magazine catch.
In Part 2. we installed the trigger guard.
In Part 3, we installed the bolt catch.
In Part 4, we installed the pivot pin.
In Part 5, we installed the trigger assembly.
In Part 6, we installed the hammer assembly.
In Part 7, we installed the selector and pistol grip.
In Part 8, we installed the takedown pin, buttstock, buffer spring and buffer.

In this…the final edition of this series…we’re going to install the complete upper, install the sights and optics, take Barack to the range, and sum it all up.

Installing the complete upper is a snap. First, place the forward mounting lug of the upper receiver into the lower receiver and line the hole up with the pivot pin.

You may want to turn it over and look at the holes from the back side to make sure you get them lined up.

Once it’s all lined up, just push the pin in.

You’ll feel some resistance from the detent spring pressure and you should be able to feel the detent snap into place as the pin seats completely.

The next step is optional. The M-16/AR-15 design was intended to have a bit of a loose fit between the upper and lower receivers. Some contend that this impact accuracy. I’m not convinced of that, but I do know that I don’t like things rattling any more than they have to so I prefer a tight fit.

Considering that I got the upper and lower from two different vendors, mine actually fit pretty well, but there was a slight bit of movement.

To alleviate this, I purchased an “accuwedge” from Midway USA. For all of $2.99 plus shipping, it’s hard to go wrong. I actually went ahead and bought two so I’d have one for “Obama” when I finally get it built up.

The accuwedge goes into the rear of the receiver…

…with the “base” down in the bottom and the “tang” sticking up behind the takedown pin.

Then swing the upper receiver closed and into place in the lower receiver.

With the accuwedge installed, the upper probably won’t seat completely into the lower on its own.

You’ll have to squeeze them together…

…and then push in the takedown pin. Again, you’ll feel the resistance of the takedown pin detent and spring and you should feel the detent pop into place as the takedown pin seats.

Now the rifle is complete; however, because I went with the flattop upper, it doesn’t do us much good without rear sights (unless you’re one of those people that the Brady’s like to talk about who “spray fire from the hip”…in which case you can skip the rest).

Considering that I’m on a budget, I couldn’t afford expensive sights and optics. I could have easily spent as much on those as I did on building the rifle…if I had that kind of money, I would have bought the parts to build up Obama already.

Basically, I cheaped out.

I bought both the iron sights and the red-dot from the same vendor:

The iron sights were only $21 but looked to have pretty standard windage and elevation adjustments and two aperture sizes. I knew I was taking a chance by buying something that cheap, but I figured if they suck too bad, I could always buy something else more expensive later.

I have to admit that, after getting them, I’m pretty impressed. For the price, they seem to be very well made. We’ll see how they do at the range.

As a carbine, I figured this rifle would be more suited for close-in work and my military buddies really like the Aimpoint red dots that they have on their M4’s so I wanted to approximate that.

I definitely wanted something that I could co-witness with the iron sights…but there was no way I could afford an Aimpoint.

After some research and reading of reviews, I decided to go with the “Sight-Mark” Aimpoint look-alike. Yes, I realize that were I a “real” operator I’d settle for nothing less than the best. I guess I’ll just have to hold off on earning my Mall Ninja merit badge for now.

The Sight-Mark I also got from for a very reasonable $78.

One disadvantage to the Sight-Mark is that the base that comes with it is not high enough to co-witness with the sights…however I found out that Pro-Mag makes a cantilever sight base that will work with the Sight Mark for that purpose. The most reasonable price I found for the Pro-mag sight base was Midway USA, where I got one for $45. Oh by the way…did I mention that I have a Curio and Relic FFL and so Midway USA gives me the dealer price? If you don’t get the dealer discount, the price for this mount is $67.

Mounting the sights is very easy. Open up the clamp on the base as far as it will go.

I put some blue thread locking compound on the threads to make sure that it stays tight.

Put one side of the base onto the flattop rail and rock it down into position.

Then tighten the base by turning the knob until it’s good and snug.

I used a large screwdriver to tighten it another half turn or so to make sure it wouldn’t come loose.

I put the rear sight all the way to the rear on the rail. The rear of the sight was formed to match the rear silhouette of the receiver so I just matched the rear edges up and put it there.

For the red-dot the procedure is pretty much the same.

Open the base all the way and put a little blue thread locking compound on the threads.

Figure out where you want it positioned…

I wanted the red dot to be relatively centered on the rifle fore and aft so that’s how I chose my mounting position. This was purely aesthetic. The only real concern is not to put it so close to the rear sight that the flip up cover hits the iron sight when opening or closing.

…rock it onto the rail…

…and tighten down the wing nut.

One thing I really like about the Pro-mag sight base is that it has a compartment for storing extra batteries.

And now we have a complete, useable rifle.

‘Course I STILL need to get a sling…

The next thing to do is take it to the range and see how it shoots.

I went to Camp Allen Weapons Range at a local Marine Corps base. It is the newest, and best indoor range around…unfortunately, it’s only open to military, LEO, military retirees and DOD employees.

I guess that’s a good thing because it would always be packed if it was open to the public.

It’s only 25 yards, but you can use anything up to and including .50BMG and they even allow black powder, which is VERY unusual for an indoor range.

The ventilation system is pretty impressive. Black powder smoke is gone almost as soon as it leaves the barrel.

I have to say that I’m very happy with both the iron sights and the Sight-Mark. I zeroed them both at 25 yards and it shot very well.

This is prone with the iron sights. I believe it was ten rounds, but I could be off by one or two. The squares are 1″.

Keep in mind that this was without a rest or even a sling. I was resting my support arm on the ground and that’s all the support I had.

And this is with the red dot, standing, off-hand.

I’m thinking for close-in work, that’ll do the job.

I did get a chance to take it to the outdoor range a week or so ago and shot at 50 yards. I didn’t have a lot of time so I didn’t take it to 100 because I wanted to get in some pistol work too…but I got similar results at 50. After reading some other opinions, I think I’m going to zero both sights at 75 yards on this rifle, which, according to what I read, should give me a good “center of mass” battle zero for any range up to 200.

I have to say that I’m pretty impressed with both sighting systems so far. I don’t think you can do much better than that for the price. The zeros stayed true between range sessions and I had no problems zeroing them or co-witnessing them. They both seem to be pretty well built and solid.

Only time will tell how they will hold up with use, but if I have any problems I’ll be sure to report them right away.

I already mentioned the one little glitch I had with the rifle itself: while firing the first magazine, it was basically a single shot. I had to cycle the selector between safe and fire between each shot to get it to fire. After that first magazine, though, I’ve had no further problems.

The trigger is a little creepy and the letoff isn’t as crisp as I’d like so I’ll be doing some trigger work shortly, but other than that, I’m very happy with my project.

Thanks for coming along for the ride and for your patience in slogging through all the pictures and my wordy descriptions.

And, with that, I’ll close this series with one final picture.


4 thoughts on “AR-15 Build Part 9

  1. Thanks for your postings about building an AR. I’m also in the process of building one. How do you like your UTG rear sight and your Sight-Mark/Aimpoint clone? How are they holding up?

  2. Well, I've had the sights on for several months now and have put a couple hundred rounds downrange to date.

    So far I'm very happy with both sight systems. They cowitnessed perfectly, they both hold zero between range sessions and have held up very well. No problems so far.

    The only thing about my whole rifle build that I'm not happy with is the trigger. I bought a fairly cheap lower parts kit. For most of the pieces this was no big deal, but the trigger is terrible. Gritty, way too much creep and too heavy.

    I'm going to do a trigger job eventually, but I just haven't had time yet.

    I've also still got another lower to build up. I just recently ordered a YHM A2 stripped upper. I'm going to put the upper together myself on the next one too. I'm going to try to build a National Match rifle good enough and in time for the Atlantic Fleet and all Navy rifle and pistol matches next spring.

    Wish me luck.

  3. Pingback: Follow Up | Captain of a Crew of One

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