National Match rifle project update.

I’m making progress on my NM AR-15 project.

I ordered all of the small parts from Midway USA a few weeks ago, a mix of DPMS and Olympic Arms parts. A couple of things are on backorder (pivot and takedown pin detent springs and the charging handle assembly), but I’ve got most of the odds and ends to put both the upper and lower together.

One thing I’m going to do is collect all the parts before getting started putting it all together. My son is really interested in helping me with this and learning about AR-15’s. He’s got limited time so I’ll probably wait and build the whole thing with him in one or two sessions after we get all the parts together.

As far as the more expensive parts, I ordered a barrel yesterday (I guess you could call it a birthday present for myself), as well as the assembly tools I’ll need and a few more small parts (including a couple of 20 round magazines).

I ended up having to settle for a lower range barrel than I would have liked to have. Every big name barrel maker is at least 5 to 6 months behind on orders. I would have been perfectly happy to spend up to $400 on a barrel if I could have gotten one from a big name maker in a reasonable amount of time.

The only place I found with a DCM approved match barrel that even came close to matching my specs was a DPMS carried by Midway USA. I looked and made phone calls, and google searches, and researched specs for two weeks before making this decision so it wasn’t done lightly…but I still hope I don’t regret it.

I must say that the price is right, and the reviews that the barrel has gotten have been pretty universally good. I ended up getting the DPMS 20″ Stainless Steel HBAR countour in .223 with 1×8 rifling. The one they have in stock is the model threaded for a flash hider. I don’t see any need for a flash hider on a competition rifle, but that’s all they had and the DPMS web site says that all barrels are on indefinite backorder, so I don’t see them getting any “post ban” non-threaded barrels in any time soon. I really wanted the .223 Wylde chamber dimensions also and this one is chambered in .223 Rem. The .223 Rem chambering is supposedly more accurate because of the reduced leade, but I can’t shoot 5.56 ammo in it so I’ll have to be careful about that.

It does have an adjustable FSB installed, so I won’t have to worry about getting Machine work done as I would have if I had ordered a stripped barrel from one of the bigger manufacturers. I was worried about that. I don’t know the gunsmiths around here well enough to know who to trust with that and I simply don’t have the tools to do precision machining.

So, anyway, I went ahead and ordered the barrel even though it’s not exactly what I wanted. it was only $149 with my dealer discount at Midway USA so it does fit into the “tight budget” aspect and getting the barrel so cheap will mean that I’ll hopefully be able to finish the whole project a little sooner than I originally thought. I figure by the time I shoot this barrel out in a few years, the AR feeding frenzy will have died down and I’ll be able to get a White Oaks or other higher-end barrel in a reasonable amount of time. Even if I can’t, when the round count starts getting up there, I can always order a replacement barrel at least six months out so that I’ll have it before the old one is completely gone…assuming that AR’s haven’t been banned by then and I can still get a barrel at all.

Also, I got another important piece of my build at a very much reduced cost. Anyone who read the comments to my last post on this project might remember that Gregory of West By God! left a comment offering a BCG in trade for an SKS trigger job. Of course I jumped at that so I got a complete, never used Bolt Carrier Group for the cost of shipping, a set of SKS Wolff replacement springs and a few hours of work. What a great deal…and I heartily thank Gregory for making the offer. I sincerely hope he’s happy with the reworked trigger.

At any rate, here’s where I’m at so far:


NM Rifle Build costs
CMMG Stripped Lower $125.99
YHM A2 Stripped Upper $69.00
Lower Parts $39.19
Upper Parts $27.97
Barrel Parts $22.16
DPMS Barrel $148.99
Bolt Carrier Group *$66.65
Magazines (2) $22.98
Tools $49.96
Taxes/Shipping/Handling $33.75
Running Total $606.64

*BCG cost includes parts, estimated labor and shipping for the SKS trigger job traded for the BCG

I’ve pretty much decided where I’m going to get the remaining parts.

From Rock River, I still need the Free Float tube and handguard ($115), the 1/4 moa NM sights ($110) and the buttstock assembly ($65). From Bushmaster, I need their adjustable 2 stage trigger (127.95) and their sight and muzzle cover set (14.95). And weights from Ray-Vin (37.90 for the set).

It’s looking like I’m going to get this done for right around $1100.00. Not bad. I would have preferred to put another $150 or $200 into it and gotten a better barrel…but whaddaya gonna do? And yes…I realize I’m not really saving money here…that I probably could have gotten a ready made RRA or Bushmaster DCM rifle for not much more than this…but half of the purpose of this project is the satisfaction and experience of assembling it myself.

My new project

I’ve got a bunch of gunsmithing projects that I need to get to but I’ve just had too many other things going on lately to get to any of them.

So, of course, what I obviously need is…another project.

I’ve been trying to decide what to build with “Obama”…the second CMMG AR lower that I bought back in November of last year in memory of the election of our Dear Reader.

I was thinking about building a 6.8spc carbine on it…but I’ve got a carbine (“Barack“) and that lower would work just fine with a 6.8spc upper. I’ll still probably build a 6.8 upper at some point, but I wanted to do something different with Obama that would make it worthwhile to have the second lower…it seems silly to me to have two virtually identical ones that serve the same purpose.

Parallel to deciding what to do with this lower, I’ve wanted a National Match AR to shoot in Service Rifle competitions for a long time. When I shoot with the Navy Marksmanship team I usually use one of the loaner rifles. They are all excellent and well cared for and shoot way better than I do, but I’ve wanted one of my own for a long time.

I think you can see where I’m going with this.

I’m going to build (or, more accurately, assemble) a National Match AR on my second CMMG lower. Considering that I’ll just basically be putting parts together, I see no reason that, with some care, thought and patience, I can’t put together a sub-moa rifle…so that’s what I’m gonna do.

I have been kicking this around for awhile now, but what finally got me off the pot was a sale an A-2 stripped uppers from Yankee Hill Machine. They’re normal price of $99.00 was reduced to $69.00 and I just decided I couldn’t pass it up.

So, here you go; the beginnings of the Sailorcurt Arms National Match AR-15:

CMMG lower, YHM A-2 upper. Yes, I noticed that the finishes don’t match. When you’re on a budget you can’t really worry too much about aesthetics…as long as it puts the holes where I’m pointing it, I can’t be too picky about finish.

After I win the lotto, I’ll build another one and have Lauer Custom Weaponry duracoat it in Ocean Camoflauge in memory of my 21 years of Navy service.

Anyway, here’s what I’m thinking so far:

I was looking at the White Oak CMP match barrel but they only offer it in 1:7 twist which I think is a bit too fast. I’d like to keep the option of shooting lighter bullet weights open, even if it will be primarily used for the heavier match bullets.

Another option is the Shilen Stainless Steel HBAR Match Barrel (with headspaced bolt) (1:8 twist, .223 Wylde Chamber) from Midway USA. It’s a bit more expensive, but is in the twist rate that I want, and I really don’t see any purpose for the flash hider on a competition barrel. The issue with that one is: will I have to take it to a gunsmith to get the holes cut for the FSB taper pins? That will add another expense. I’d try it myself, but I just don’t have the equipment for that.

There are a couple of other options I’m looking at, but those two look the best so far.

For my trigger choices, I like a two stage trigger, so I’m thinking either the Bushmaster (If they ever get them back in stock), or the Rock River Arms two stage. I thought about Geissele or Jewell, but the budget is of concern. If I have an extra $100 or so laying around, I may choose one of the higher end models.

For sights, the Rock River 1/4moa x 1/4moa seens like the best deal. For $110 you get both the rear sight assembly and the front NM sight post. Midway USA also has a Bushmaster 1/4 x 1/4 MOA rear sight for slightly more. If I get to the point where $40 is critical, I can always go with the less expensive DPMS 1/4 x 1/2 moa sight from Midway.

For the free float handguard, there are many choices but they’re all in the same price range. The DPMS from Midway seems to be the best price I could find, but one reviewer didn’t like the location of the sling swivel mount. If I end up ordering the Rock River Arms trigger and/or sights, it would be convenient just to order their Free Float barrel sleeve and handguard at the same time…besides, I know that I’d be happy with how that handguard looks and functions because I’ve used Rock River Arms rifles before.

As far as balance weights, Ray Vin seems to be the best priced solution for that…short of just making my own. Their prices are pretty good though. Using fishing weights or lead shot probably wouldn’t be much cheaper, and would require labor to form and attach to keep them from shifting around.

All the other parts will pretty much just be well made standard parts. I see no need for expensive “match grade” bolt carriers or gas tubes or other parts that have minimal impact on accuracy. The lightweight bolt carrier I can actually understand, but I seriously doubt that the benefit would be worth the added expense.

I’m thinking that the best money spent on match grade parts will be on the ones listed above.

Anyone have any insights or tips that could help me with this project? Input and advice is welcome.

I’m going to use the posts relating to this to keep track of the costs as well as my progress and results. To that end, here’s what I’ve got into it so far:

NM Rifle Build costs
CMMG Stripped Lower $125.99
YHM A2 Stripped Upper $69.00
Taxes/Shipping/Handling $18.80
Running Total $213.79

Info Bleg

At the gun show today, there was a vendor selling A3 style flattop stripped AR uppers for $95.

My last AR, I assembled the lower and bought the upper complete. For my next one, I’d like to assemble the upper too. I’m thinking 6.8spc…but that’s not the nature of my question.

When I asked the seller what the make of the uppers was, he said he didn’t know. I did notice a mark on the right side of the upper, but other than that, nothing to identify the manufacturer.

I didn’t want to buy some crap that wouldn’t work and not be able to get my money back, so I passed on it.

I did some research after I got home, though and it appears to me that the mark I remember was an Omega symbol and seems to be typical of YHM uppers. Anyone know if that is a reliable indicator?

Another thing that I noticed was that the rails had no “T” marks. All of the YHM A3 uppers I found online said that they were “T” marked. Could it just be that these are older ones without the markings? Or are they not YHM after all?

Are there any counterfeit AR parts around that I need to be leery of?

Next, if these are YHM uppers, does $95 seem like a “can’t pass up” kind of price? I found a price range online of anywhere from about that, to $125. Buying online, I’d have to pay somewhere around $7 for shipping as well.

I’d hate to pass this up and then end up paying a lot more later…but I’d also hate to buy a POS and regret it later.

Any advice before tomorrow afternoon would be appreciated. I’ve gotta decide before the show closes at 4:00 Eastern time.

Thanks in advance.

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.

AR-15 Build Part 8

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.

This time we’re going to install the takedown pin, buttstock, buffer spring and buffer.

This part wasn’t explained well in the arfcom instructions so I had to find another thread on arfcom that covered installing the M4 buttstock. It wasn’t hard, but I wanted to be sure I was putting everything in the right way.

The first thing we’re going to do is put the locking ring onto the buttstock. The ring should be installed with the castellations facing aft toward the butt.

Then the backplate is installed. The backplate has a tab that fits in a groove in the threads of the buttstock tube that ensures it stays aligned. Also, there is a stamped “well” in the bottom part of the backplate. The protruding part of the well should be forward, towards the receiver.

Next, insert the takedown pin into the hole in the receiver from the right side. It should be installed so that the groove in the body of the pin is facing aft.

In the rear of the receiver, there is a small hole that the takedown pin detent goes into.

And then the detent spring goes in the same hole after the detent.

Sorry about the blurry photo. I’ve still got that same crappy camera I’ve been complaining about for years. As long as it works, I can’t justify the expense of buying a new one…the darn thing just won’t break.

I’ve thought I’ve killed it a couple of times, but taking the batteries out and putting them back in (the digital camera version of control-alt-delete?) brought it back to life each time.

Now start screwing the buttstock tube into the rear of the receiver. Hold the receiver aft end up so that the detent spring and detent don’t fall out.

It just occurred to me that I’ve reverted to my Navy days and have started occasionally using the terms “aft” and “forward”. Versus going back and trying to find and correct all the times I’ve used those terms: “aft” means the back, the rear, the posterior aspect; forward means the front, the head, the anterior aspect. On a ship, aft is the blunt end and forward is the pointy end.

On a rifle, aft is the end you should be on and forward is the end that should be pointing at your target.

If I start using “port” and “starboard”, you have my permission to whack me in the back of the head.

Anyway, only screw it in until just before the tube begins to cover the buffer retainer hole in the bottom of the rear part of the receiver.

Then drop the buffer retainer spring into the retainer hole.

Put the buffer retainer over the spring.

Then press the retainer down and screw the buttstock in a couple more turns.

You want the buttstock tube to prevent the retainer from coming out of the hole, but not restrict its up and down movement. The pin on the top of the buffer retainer should stick up slightly beyond the inside edge of the buttstock tube.

Next, push the backplate forward on the tube to seat it against the rear of the receiver. This will compress the takedown pin detent spring. As you first start compressing the spring would be a good time to rotate the takedown pin a little and be sure the detent is seated in the groove in the takedown pin body.

The protruding part of the stamped well in the backplate will help insure that the backplate is aligned properly with the reciever. The tab on the backplate, locked into the groove in the buttstock tube threads, ensures that the buttstock is properly aligned to the receiver.

Screw the locking ring down by hand and then tighten it snug with a telescoping stock wrench, spanner wrench or whatever tool you can get to work.

It probably wouldn’t hurt to put some thread locking compound on the threads before tightening to help keep the locking ring from backing out. I didn’t (this time) but if I have trouble with it loosening up, I will.

Next, insert the buffer spring into the buttstock tube. It is probably easier to do this with the hammer cocked, as that will get it more out of the way.

Then the buffer is installed with the shaft fitting inside the spring. Press down on the buffer retainer to get the front of the buffer into the tube.

And that’s it.

The lower is now complete.

Next time, we’ll install the assembled upper, take Barack to the range and finish up the series.

Final Post in the series

AR-15 Build Part 7

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.

This time, we’re going to install the selector switch and pistol grip.

For some unknown reason, I didn’t take any pictures of installing the selector switch into the receiver. It isn’t exactly rocket science, but I generally take pictures of everything just to be thorough (you don’t see all the ones I decide are redundant and choose not to post). I don’t know why this one slipped through the cracks. I plan to do a trigger job on this rifle so when I disassemble it for that, I’ll take that apart too and take a picture to update this post.

At any rate, before installing the selector, cock the hammer. Then the selector goes in from the left side of the receiver with the selector pointing to the “fire” position (pointer up, thumb button down).

Next, the selector detent goes into the well on the bottom/right side of the receiver. The detent goes in with the pointed end toward the selector.

The detent spring goes into the well in right side of the pistol grip.

You’ll probably need to keep your finger on the selector to keep it in position while installing the pistol grip and detent spring.

Next, slide the pistol grip onto the receiver ensuring that the detent spring mates with the bottom of the selector detent.

On mine, the grip fit tightly enough that, once seated completely, I could let go of it; it was secure enough to stay in place on its own while I installed the grip screw.

Put the lock washer onto the grip screw.

Then install the screw through the bottom of the pistol grip. It’s a tight space in there so you may want to use some needle nose pliers to get it started and remember that the receiver is aluminum; it wouldn’t take much to strip the threads so be careful not to crossthread the screw and don’t use gorilla torque to tighten it.


Only two “parts” left.

Next we’ll install the takedown pin, buttstock, buffer spring and buffer and our lower will be complete.

Next Post in the series

AR-15 Build Part 6

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.

This time, we’re going to install the hammer.

There is a pin called the “J-pin” that goes into the bottom of the hammer and pokes up into the mounting hole. This pin is what locks into the center groove in the hammer pin in order to secure the pin and keep the hammer centered.

This pin was already installed in my hammer so I don’t have pictures or instructions for installing it, but if is not installed, it will need to be so before anything else.

Assuming that the J-pin is already installed, the first step, as with the trigger, is to install the spring. The spring is very similar to the trigger spring and goes on in much the same way (and is just as hard to describe).

The spring goes onto the hammer from the rear, with the coils facing away from the hammer, the closed squared loop up and the open legs pointing down.

As with the trigger spring, the coils go over the protrusions on either side of the hammer through which the hammer pin hole passes.

When properly installed, the closed end should be resting against the back of the hammer and the legs should be pointing down and forward.

In order to install the hammer assembly into the receiver, you have to tip it forward and place the ends of the legs on top of the trigger pin.

Then rotate it to the rear and press it forward and down against the spring tension to line it up with the mounting holes in the receiver.

Again, I used a pin punch to line it all up before installing the pin.

Be sure to insert the end of the hammer pin without the off-center groove first. In other words, if the pin is going in from the left as pictured, the off center groove should be to the left.

If you put it in the other way, the off center groove will enter the hammer first and the J-pin will lock into it…which will complicate things.

As the pin is pushing in, the punch will be pushed out the opposite side. You may have to jiggle the hammer a little to get the holes aligned and there may be some resistance as the pin pushes past J-pin in the hammer. You will feel the J-Pin lock into the groove in the hammer pin as it centers.

In this picture, you can also see the hammer spring legs clearly atop the trigger pin. The leg on the left side should seat into the groove in the trigger pin locking it into place.

Installed with the hammer cocked.

And, from the side with the hammer decocked.

Don’t dry fire the lower receiver without the upper installed. The hammer will impact the aluminum receiver and the bolt catch and may damage either or both.

That’s all there is to it.

We’re almost done. Next time we’ll install the selector switch and pistol grip.

Next Post in the series

AR-15 Build Part 5

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.

This time, we’re going to install the trigger assembly.

The first step is to place the trigger spring onto the trigger.

It’s kind of hard to describe in words. The trigger spring has two closed coils that go over the protruding part of the trigger pin/pivot point area.

Coming off the coils are a closed, squared off loop on one side and two open “legs” on the other side.

To install the spring, start from the bottom front of the trigger and put the spring onto the trigger with the coils up and to the rear, the closed loop end up and toward the front and the “legs” down and toward the front.

I found it easier to tilt the spring so that I could put the coil on one side over the pivot point protrusion first, then pry the spring farther open to pop the others coil onto the other side of the protrusion.

When it’s on correctly, the closed loop should rest against the underside of the front horizontal surface of the trigger and the “legs” should stick out forward and down.

Not a very eloquent explanation, but that’s the best I can do without knowing the technical terms for the various protrusions and elements of the trigger.

Next, the disconnector spring goes into a well in the top of the trigger.

The disconnector spring is slightly larger in diameter at one end than the other. The larger end goes into the well.

The spring should snap into place, which should prevent it from falling back out.

Then the disconnector is placed over the spring.

There is an open, squared off cutout in the rear of the disconnector that seats over the disconnector spring. The hole in the disconnector aligns with the trigger pin/pivot point on the trigger. When installed, the trigger pin holds both the trigger and disconnector in place.

Then, while holding the disconnector in place with your finger, the trigger/disconnector assembly is placed into the receiver from the top, the trigger should poke through the hole in the receiver into the trigger guard area.

I used a pin punch to hold the trigger and disconnector assembly in the receiver while installing the trigger pin.

You will have to press the trigger/disconnector down against the spring tension of the trigger spring to get the holes aligned.

Then insert the trigger pin and, in the process push the pin punch out.

There are two grooves in the trigger pin (which is, incidentally, identical to the hammer pin)…one in the center and one off to one side.

The center groove is used on the hammer pin but serves no obvious purpose on the trigger. The off-center groove is what holds the trigger pin in place. When the hammer is installed, one of the legs in the hammer spring will lock into this groove in the trigger pin, which locks it in place.

It doesn’t matter which way the trigger pin is installed, but (according to the arfcom instructions) it is common practice to install it with the off-center groove to the left.

You will probably have to jiggle the trigger and disconnector a little as the pin is going in to get all the holes aligned.

All done.

Next time we’ll install the hammer.

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AR-15 Build Part 4

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.

This time, we’re going to install the pivot pin.

First I used a small drill bit to make sure there were no burrs inside the spring/detent hole on the right side of the receiver. It was clear.

Then put receiver in the hobby vise again, only this time with the front of the receiver up.

Then the pivot pin detent spring drops into the spring/detent well.

The detent goes on top of the spring. The spring is long enough that the detent sits on top of it outside the well and will just fall of you let go of it. The spring has to be compressed and the detent pushed into the hole while installing the pivot pin.

I have read that this is the most difficult part of assembly if you try to do it without the special pivot pin installation tool. This is where I “invented” a new procedure that made installing the pivot pin a snap.

I noticed that, as the pivot pin is inserted into the holes on the mounting ears on the front of the receiver, there is a gap between the pin body and the top of the spring/detent well.

I surmised that a thin, flat piece of metal, stiff enough to hold the detent down, but thin enough to fit into that gap would enable me to install the pivot pin easily.

I then occurred to me that feeler gauges are stiff but thin pieces of metal…and they come in a selection of sizes…surely one of them would fit the bill. After a little experimentation, I decided that a .014″ feeler gauge was the right size for fitting in the gap, but allowing the pivot pin to be installed easily.

I pushed the detent down into the well as far as I could with my needle nose pliers, then used the feeler gauge to push it the rest of the way down and hold it in place against the spring tension.

Then just slid the pivot pin into the holes in the mounting ears over top of the feeler gauge.

Once the pin was in as far as it would go with the feeler gauge in place, I just pulled the gauge out…

…and rotated the pin so that the detent popped into the groove.

No muss, no fuss and no special tools required.

And there you have it.

Next time we’ll install the trigger assembly.

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AR-15 Build Part 3

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.

This time we’re going to install the bolt catch. This was probably the most difficult part of the whole thing…which isn’t really saying much because it wasn’t hard either.

As usual…click all pix to make bigger

This is one of the times that I used my hobby vise.

I’m sure you could do this without the vise, but I can’t tell you how many times this has made a job that would have required three hands, a snap.

The vise’s gripping head is adjustable in all directions so it can be oriented pretty much however you need it. In this case, I turned and tilted it to hold the receiver on end with the rear of the receiver up.

I used standard plastic packing tape to shield the receiver from scratches and marring. I used two layers just to make sure it was thick enough.

The mounting ears for the bolt catch are on the left side of the receiver just aft of the magazine well.

The roll pin that holds the catch in place needs to be started (unless you really DO have three hands). Needle nose pliers (or a roll pin holder if you have one) is used to align the pin with the hole in the catch mounting ears on the receiver.

I got it started by gently tapping with my brass mallet. Again…that whole “not enough hands” thing. There was no way to hold the pin straight with the pliers, hold a pin or roll pin punch and tap it with the mallet all at the same time.

Carefully tapping with the mallet worked to get it started.

Then I used my long pin punch to seat the pin far enough to be firmly started. Don’t drive it in too far, you don’t want it to go all the way through the first ear and protrude into the area where the bolt catch still needs to be installed.

Next, the bolt catch spring goes into the hole in between the bolt catch mounting ears.

Then the bolt catch buffer goes on top of the spring.

And now it’s ready for the bolt catch itself.

The bolt catch goes in with the release button sticking up above the top of the receiver. It should only go in one way so it’s pretty self explanatory.

You’ll have to hold the catch in against spring tension while the pin is being driven the rest of the way in. Probably the easiest way to keep the holes aligned properly while the pin is being driven is to use a pin punch to hold it all together. You may notice that I put a little tape between the pin punch and receiver to protect the finish. Probably overkill, but I didn’t want to take any chances.

I pressed the pin punch against the edge of the work bench to keep it from falling out while driving the pin.

Them, as the roll pin is being driven in, it pushes the pin punch out of the hole.

And there you have it.

Again, if you mar the edges of the bolt catch mounting ears or the receiver, a little Aluminum Black will fix it right up.

Next up: installing the pivot pin.

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