I’m going to consider this part one of the series even though I’ve been talking about this for a while now; this is the first of the series that involves the actual assembly and not just picking parts and buying stuff.
Anyone interested in the backstory regarding my reasons for assembling this rifle, the components that I chose and why, the costs incurred, etc can click HERE for all of those preliminary posts. I changed the category of the preliminary posts to “NM Rifle Pre-build” to differentiate them from the actual assembly series posts.
Although I’ve already done a post series on assembling an AR-15 lower, I’m going to repeat those steps here for the sake of thoroughness. the only real differences between this one and the other one I did are that this one uses an A-2 style buttstock so that assembly is slightly different, and the Jewell match trigger installation is significantly different. If you’re interested in assembling a lower with a standard trigger and an M4 style collapsible buttstock, the final post of that series (with links to the other posts in the series) can be found HERE.
As usual…click all pix to make bigger
Doesn’t look all that daunting once you get it all spread out does it?
I should have taken a picture with all the little pieces parts just dumped into a big ziplock bag. Now THAT made it look complicated.
To recap (and because I’m sure someone stumbling across this who has’t read any of the preliminary posts linked above is going to ask), the lower is a CMMG. The Upper is a YHM, the Barrel is a DPMS .223, Stainless Steel, DCM Legal, 1:8 twist, 20″ HBAR. The trigger is a Jewell 2 stage adjustable match trigger. The free float tube, handguards, Buttstock assembly, 1/4 moa x 1/4 moa rear sight and front sight post are all from Rock River Arms. The Bolt Carrier Group I don’t know the make but I got it in trade for an SKS trigger job so I wasn’t being picky. The magazines are steel 20 rounders from C-Products. The charging handle is from Model 1 and all the small parts are a mix of DPMS and Olympic depending what MidwayUSA had in stock, what got the best reviews and what was the least expensive, in that order. For costs and the reasoning (or lack thereof) for all of my selections, please click link above to the pre-build posts…I discussed all that in great detail there.
The lower assembly doesn’t require any particular special tools. Everything for the lower is pretty standard fare: pin punches, needle nose pliers, hammer etc.
The upper only requires a couple of specialized tools: the Armorer’s Action Block, the AR-15 multi-tool (or a barrel nut wrench, combined with a spanner wrench and an appropriate sized open end wrench for the flash hider), and snap ring pliers and a torque wrench (which are pretty standard for piston-heads, and can be purchased or rented at virtually any auto parts store).
The packing tape is needed for installing the bolt catch pin and is only used to prevent the lower receiver finish from being marred during installation. It can be used at any phase of the assembly to protect the finish, but is really only needed for the bolt catch pin.
The dremel tool, jewelers file, fine stone and cold blue were only needed because I was installing a free float tube with a standard A2 Front Sight Base (FSB). The Free float tube has the front sling swivel mounted on it. In order for it to fit correctly, the sling swivel mounting ears on the FSB have to be ground or cut off. Then the area that is cut must be re-finished with cold blue to prevent corrosion and to match the finish. If you’re doing a standard installation without the free-float tube, or using an FSB or gas block that doesn’t have an integral sling swivel mount, these tools aren’t required.
The Jewell trigger tools came with the trigger assembly. The two allen wrenches were also required for the trigger for adjustment purposes…conveniently, the large allen wrench used for the trigger was also the size needed for the FSB set screws that, on a match rifle, replace the taper pins.
The snap ring pliers, torque wrench and multi-tool are needed for barrel installation. The torque wrench needs to go to at least 30 foot pounds and should be 1/2″ drive. If a 3/8″ drive torque wrench is used, a 3/8″ to 1/2″ socket adapter will be needed to fit the torque wrench to the hole in the multi-tool.
The home-made A2 sight tool is only needed if you are assembling an A-2 upper that doesn’t have rear sights already installed. I made that on the fly when I realized that I really did need it. I saw A-2 sight tools for sale but decided I could manage without one…I was right…it was easy to make one out of a humble popsicle stick that worked just fine.
The big straight slot screwdriver is used for the Lower Receiver extension self-locking screw (aka upper buttstock screw) and the pistol grip screw. There are different types of pistol grip screws so be sure you have a long driver for the type of screw you have, whether allen head, phillips, or whatever.
Not pictured is my bench vise…pretty much a must have for assembling an upper receiver. It would be very difficult, if not impossible, to properly torque the barrel nut without one and it makes several other parts of the assembly much easier.
The Armorer’s block is really only needed for installing the barrel, but it is very useful for holding the upper receiver during several stages of the assembly. I actually bought an Armorer’s block set which also came with a lower action block as well as the upper action block. The lower action block is basically a chunk of plastic shaped like a magazine. It locks into the magazine well in the lower and then clamps in a vise to hold the lower while working.
During my last lower build, I used a rubber-jawed hobby vise to hold the lower during the assembly. This time, I had an assistant (my son) and those two extra hands meant I didn’t need either the hobby vise or the lower action block. If you are going to be doing this on your own, I’d recommend getting the lower action block as well as the upper action block. It seems to me that the lower action block would work just as well as my hobby vise did if you only have two hands; and, at MidwayUSA, the set was only a couple dollars more than just the upper action block by itself.
You may run across an opportunity to use some other common tools, smaller screwdrivers, different sized hammers, etc…but those really just make things easier, they aren’t really required. The above tools are all that you really need to assemble an AR-15.
Stay tuned…in part 2 we’re going to start assembling the lower.