Searched, but did not see a dedicated “assembly thread”. Looking for pointers in the right direction here. If there’s a particular thread you’ve followed or video you bought that helped, or a resource online, I’d love to hear about it. I’ve watched the Brownells ones.
I’m using the following parts to assemble an upper once I get the barrel in, and I want to make sure I have to right tools, greases, etc.
-BCM’s upper receiver(the current production type) from Grant
-BCM BCG MicroSlick’ed from Grant
-ALG 13" M-LOK EMR
-Sionics mid-weight/mid-length 16" barrel with GB & gas tube
-BCM A2 birdcage and crush washer
-Loctite C5-A
-Red Loctite
I’ve googled youtube videos and searched the forum for assembly instructions. This is what seems to be the correct procedure.
Step 1-Put upper in BEV block, add bolt carrier per instructions, and install barrel.
Step 2-Apply grease(Loctite C5-A in this case) to the receiver’s threads and inside of barrel nut
Step 3-Install ALG barrel nut as directions state.
Step 4-Install gas tube into gas block, slide onto barrel.
Step 5-Apply red loctite to set screw on gas block, hand tighten snug.
Step 6-Install crush washer, add A2 Birdcage, and torque on at least 90 degrees but no more than 460 degrees.
Step 7-Attach rail to barrel nut.
Step 8-Install optic.
Step 9-Install BCG, CH, complete upper on complete lower, and do safety/function check.
Step 10-Go test fire.
Any pointers? I know I could have a gunsmith do this more me, but then I’ll never learn how to do it myself. Some of you make barrel installs seem like what you do while waiting for the toaster to pop out toast in the morning, but I don’t know what I don’t know, and I’d like to learn to do it right.
You can do it. Just do your research and take your time. I assembled an upper a few months ago and once I had all the parts and did all the necessary research it came together very quickly.
When working with the barrel assembly, be sure that everything will work correctly before applying any loctite anywhere.
I’ve paid the price for over loctiting a GB only to find my barrel nut must have been out of spec and no forend would correctly align with the upper, no matter the torque on the nut.
Then I couldn’t really remove it easily, because the loctite I was using on the GB was ungodly strong. Some type of green loctite I believe, I still use it, but in smaller quantities.
Rookie mistakes yes, but I started from the beginning without any prior knowledge.
There are more videos on youtube about this than you could watch in a lifetime.
Look for ar barrel installation, flash hider, gas block install.
Also like SilverCat said, pre assemble. Everything, de burr.
If you want to learn, read and watch everything you can, more than once if you have to.
There is no time limit. When you decide to start, rest assured if you get in a jam, asking will get you all the help you need.
Big strong muscles are great, but they shouldn’t be needed to assemble a new rifle from parts. When you do get in a jam with something, more force is usually NOT the answer.
I’ve had pretty good luck with rotating the gas block 180 degrees and aligning the gas port with the set screw hole on the gas block. The thought being that is how the manufacturer bores the gas block’s port. It is pretty quick and easy
I was thinking about this. I called and talked to Sionics this morning, and they had the same suggestion.
I’m tracking.
This sounds like a good idea. I’m hoping that by sticking to the same manufacturer with the barrel and gas block I’ll skip some of the potential tolerance stacking and mismatching issues that could come from mixing brands. I’ll see if this trick helps.
It’s not rocket science. Take your time and follow your first post instructions. The red loctite is something I use for the gas block screws. Some armorers use the tap the screw to release the tension method. This allows you to put a little more torque on the screws. You can always try this method, to test your rifle after completing the installation. If all works well, you can use red loctite after if you choose. I prefer having a mechanical lock on things to prevent them from coming loose.
The videos on you tube are a good guide. Having all of the proper tools necessary makes life much easier. I highly recommend the Reaction rod and gas block tool from Geissele.
I’m just waiting on Sionics to get the barrels back in stock. Since the upper and BCG are made by BCM, I’ve toyed around with the idea of ordering a BCM ELW barrel, but I think I’m going to wait it out and get the Sionics Mid-weight/Mid-Length. It’s cheaper, and I’d like to support Sionics as a company. Their barrel might also be better suited to my goals for this rifle. If I can set enough cash aside, I’ll even order a complete upper while the free BCGs are being offered and then go back to saving for a barrel to finish this upper. I’ve been piecing this rifle together for 5 years now, no point rushing during the home stretch.
The new BCM uppers are VERY tight. Both of my assembled uppers (BCM blem upper + Sionics LW barrel) were a super tight fit. Both required a gentile tapping to get seated into the upper, so grease the crap out of the extension.
The ALG handguard is easy to torque. With the a 12" pipe it took me VERY little effort to rotate the barrel nut into alignment, so go slow and don’t over rotate the nut cause you’re thinking it’s going to be hard. On the gas block; I install upside down and center the set screw on the port. Mark the barrel with a pencil or fine point sharpie. Rotate 180, keep the edge of the block on your mark and see if the set screws line up with the dimples. Haven’t done the second barrel yet, but the first one everything lined up perfect. My second Sionics barrel has one dimple (closest to muzzle) and a pretty huge flat 180 deg opposite the port. I can’t imagine not being able to line things up.
Also, there are LOTS of books available from Amazon that are great references for not a lot of money.
Couple of things. As TAZ said, the fit for the barrel might be very tight into the BCM upper. Mine was! The best way to get the barrel in is to HEAT THE UPPER gently with a heat gun until the barrel slides in with very minor taping. That way you won’t potentially screw anything up especially where the barrel extension alignment pin slides into the upper.
I always use red Loctite on the GB set screws. If you need to remove it, again use heat to loosen the red Loctite.
Also, be careful to use the right method for clocking the flash hider if you are using a crush washer. You want to use a tighten and back-off method until you get to the last quarter turn IIRC (look it up to be sure).
I put an ALG M-Lok 13 inch on one of my rifles to try it out. Pretty easy to install with their instructions. Works well too.
I recommend a reaction rod for some assembly. But I also use a vise block sometimes.
BTW - Make sure you have a good bench mounted vise.