NM AR Build Update

OK…I ordered the last of the essential parts for the NM AR build today.

Brownell’s had the Rock River free float tube for less than Rock River was selling them for…and had them in stock. I did find out through the review that the RR float tube does not come with the Delta ring, weld spring or snap ring. I also found out that the float tube comes with a gas tube so I wasted a little money buying one of those…oh well.

The Model 1 charging handle I had been waiting for was in stock at MidwayUSA, but the two pivot/takedown pin detent springs were still listed as backordered.

So…I cancelled the detent springs from MidwayUSA and ordered the charging handle, delta ring, weld spring and snap ring from them. Then I ordered the detent springs and the free float tube from Brownell’s. Finally, I called Rock River to verify they had them in stock…they do…and that they’d be able to ship them to me in a reasonable time…they can (about 10 days)…and ordered the NM rear sights and the buttstock kit.

So, the only things I have left are accessories…weights, muzzle and sight covers, a sling, things like that. Those can all wait.

At the bottom of this post, I’ll update my costs so far.

Before that, though…right before I left for the weekend, I got an e-mail that asked some good questions. I promised the writer an answer, but I think the questions are worth answering in public. The pertinent part of his e-mail:

First question: how is the RRA NM float tube mounted? Does it screw on over the barrel nut? Does it replace the barrel nut? Does it come with a barrel nut?

Second question: small parts for the upper. Who, what and where? I’ve seen CMMG uppers with the forward assist and ejection port cover already mounted. Might be a good idea, saves time. How do I pick a charging handle? Before someone sent you a BCG, what were you looking at?

Third question: what tools have you bought so far?

1. This will be my first experience with installing a Free Float tube. From what I’ve gleaned from the limited info I’ve found, the free float tube comes with a specific nut that replaces the barrel nut. The replacement nut screws on where the barrel nut would normally go, then the free float tube screws onto that. That’s as much as I know until I get mine in and start looking at how it all goes together. I’ll be posting the details of the build as I do it so you can learn along with me.

2. Parts for the upper. If you start out with a completely stripped upper as I did, you’ll need:

The bolt carrier group.
The charging handle, including latch, latch spring and latch pin.
The forward assist assembly including spring and retaining pin.
The ejection port cover, retaining ring, pin and spring.
Rear sight assembly.

If you get the A4 type upper, the removable carry handle may come with a rear sight assembly. Be careful of that though because some service rifle matches only allow A2 style rifles.

Many of these parts come together as a kit. I bought the ejection port cover parts, the forward assist parts and the rear sights as kits.

It’s important to do the research and find out what exactly comes with the components you order so you don’t end up spending money on duplicate parts.

As far as from whom…as long as you stay with brand name parts, I can’t see you going wrong. DPMS, Bushmaster, Olympic, Colt etc etc etc…any of them should make good quality, mil-spec parts that will work on your rifle.

I bought almost all of the small parts from MidwayUSA. I have a curio and relic FFL so I get the dealer price from them, which made their prices better than anywhere else. Which specific manufacturer I chose depended on a few factors: What was in stock, Customer reviews, and price…in that order. One of the best features of MidwayUSA is their customer reviews. That’s what prompted me to buy the buttstock from RRA rather than one of the brands that MidwayUSA carries. All of the buttstocks that MidwayUSA had got some bad reviews for fit, finish, quality etc.

Most of the small parts I ordered were either DPMS or Olympic.

In addition to the small upper parts, you’ll need the barrel and the small parts for it.

When ordering a barrel, it is important to note on the ones that don’t have the front sight already installed, you’ll probably have to have the holes for the taper pins drilled both in the barrel and in the front sight itself; or, if you go with the adjustable front sight setup, you’ll have to have the FSB drilled and tapped for the set screws and flats milled in the barrel for the set screws to mate with.

That’s part of the reason I went with the barrel that I did…it was already outfitted with the FSB. I could have handled drilling and tapping the FSB for set screws, but milling the flats in the barrel is beyond my capabilities…mainly because I don’t have a milling machine.

The other parts you’ll need for the barrel are:

The front sight assembly (if it didn’t come with the barrel)
The Free float tube and handguards (which should include the barrel nut)
The sling swivel and rivet (if they don’t come with the free float tube)
The Delta Ring, weld spring and snap ring (may come with the free float tube)
The gas tube and gas tube pin (may come with the free float tube)
The flash supresser and peel washer for a threaded barrel. (if they don’t come with the barrel)

As you can see, it’s important to know what exactly comes with the parts you’re ordering before ordering anything else.

As far as choosing a charging handle…the main thing is to get a stock, military style handle. DCM/CMP/NRA service rifles must have the external appearance (other than the barrel) of an issued service rifle, so the charging handle can’t be oversized or have extended or “tactical” latches. I ended up ordering the Model 1…primarily because it was the only standard one they had in stock. I wouldn’t have ordered it solely for that reason, but the price was right and it got decent reviews also. I figured, even if it doesn’t hold up, I can order a better one later on if I need to. They are easy to change.

I was originally going to get a reduced weight “national match” bolt carrier group, but decided against it. I just don’t think that will have enough impact on accuracy to justify the extra expense. With that in mind, any brand name, mil-spec BCG should work just fine. I was looking at the Bushmaster BCG from MidwayUSA. The price is reasonable, Bushmaster is a well known name in the AR world, and they got excellent customer reviews. The downside is that they are out of stock right now. I can’t imagine that you would go wrong with the DPMS, Olympic, Les Bauer, Daniel Defense, or any of the other brands that they have in stock.

I had heard of some people having problems finding a bolt that would headspace correctly with their match barrel so I bought the headspace gauges to check mine. It was probably a waste of money though because it checked out fine…as I suspect the vast majority would…but better safe than sorry right? If you don’t want to spend the money on the gauges, disassemble the bolt and take the bolt and barrel to a gunsmith. It only takes a minute to check headspace if you take the disassembled parts in to them.

One other note on parts: some people think it is important to get a matched upper and lower set for a tight fit. I disagree. I think an accu-wedge or one of the other methods of tightening the fit will work just fine. Of course, I’m not a world-class shooter who depends on that last fraction of an MOA of performance to make the difference so your mileage may vary.

3. Tools.

I already have pin punches. Roll pin punches probably wouldn’t hurt anything, but I’ve been able to do everything I’ve needed to do with standard pin punches so far.

I bought the headspace gauges but you really don’t need them…those are rather expensive for what they are…about $20 each for the go and no-go gauges. You can save yourself about $40 in tools by skipping them.

I bought the DPMS AR multi-tool. It’s needed for installing the barrel, free float tube and buttstock. There are cheaper knockoffs out there, but from what I read in the reviews, it’s worth it to spend a few extra bucks on the DPMS one.

I bought the Model 1 upper and lower receiver “action blocks”.

A barrel clamp probably wouldn’t hurt anything, but I think I can make do without one. If I need to clamp the barrel, I’ll make a clamp out of wood.

I’ve already got a torque wrench for tightening the barrel nut, but if you don’t have one, you should be able to borrow or rent one from your local auto parts store.

There are other small tools (gas tube alignment tools, gas tube roll pin punch, things like that) but I think standard tools will do just fine, I don’t see any need for something that specific. If I have trouble during the assembly and have to buy any of those specific tools, I’ll burn those bridges when I come to them. Also, I’m including the cost of tools to the total cost of the build because they are expenses that I’ve incurred during the course of this project, but I’m not going to include them in the cost of the rifle once I’m done…tools are useful beyond the one project they were purchased for so their price is not properly included in the cost of the rifle.

Again, this is my first upper build and my first NM build so I’m kind of playing it by ear. I’ll really find out if I made the right decisions as I’m putting it together and during that all important first range trip after it’s done.

Stick with me and we’ll work our way through this together.

And now…the current cost tally:

NM Rifle Build costs
CMMG Stripped Lower $125.99
YHM A2 Stripped Upper $69.00
Lower Parts $46.08
Upper Parts $43.38
Barrel Parts $35.12
DPMS Barrel $148.99
RRA NM Free Float Tube/Handguard $100.00
RRA NM Sight Assembly $110.00
RRA A2 Buttstock Kit $65
Bolt Carrier Group *$66.65
Jewell Trigger $203.99
Magazines (2) $22.98
Tools $83.94
Taxes/Shipping/Handling $57.11
Running Total $1178.23

Those are all the parts I need for the build. The only things left are some accessories: Barrel and buttstock weights, muzzle and sight covers, sling and possibly a hard case.

The only one of those things actually required for a match rifle is the sling. A good, leather NM sling is about $40 to $50. The muzzle and sight covers are about $15, the weights are about $40 and a decent hard gun case can be had for around $100.

You wanna know the really frustrating thing? I just found out that the Norfolk County Rifle Range is conducting an NRA High Power Rifle match at the Blackwater facility on September 19. Unfortunately, I won’t even have all the parts in by then, let alone have time to build it, break it in and check it out thoroughly.


I suppose I could shoot my Garand in the match, even though it isn’t a NM rifle. It would at least give me some practice at the appropriate distances rather than using reduced targets at 100 yards. I’ll have to think about it.


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