Assembling an upper receiver for an AR

[HOOfan_1]

Hardest part on assembling the upper for me was getting the roll pin in on the forward assist.

I had the correct vise blocks, a really good barrel wrench and a torque wrench. I had to use a lot more torque than I thought I would though....I think I went to 60 ft-lb. I believe the range is 30-80 ft.lb

The suggested way to torque it though is to go 30-32 ft-lb. break it loose, re-torque to 30-32 ft-lb. break it loose, retorque to 30-32 ft-lb. break loose and then torque it as needed to line up the holes on the barrel nut and the upper to feed the gas tube through.

 

[wally]

Most folks just buy an upper assembly.

^^^ This because unless you are lucky or good at catching sales on quality parts the savings are minimal.

I've used a variation of AlexanderA's method to disassemble/re-assemble uppers to install free float tubes but I didn't sit on anything, just the rifle squeezed between my knees was fine. Generally getting the flash hider off is the biggest issue -- barrel in a vice with leather pads, and sometimes, especially with well used rifles, penetrating oil, time to sit, and heat from a propane touch has been required.


Really, 70 ft-lbs is not all that much torque -- about like a biceps curl with a 65lb dumbbell -- and frankly if new parts broke from doing this I'd be glad I didn't fire it, would operationally define substandard to me!

 

[HOOfan_1]

^^^ This because unless you are lucky or good at catching sales on quality parts the savings are minimal.

Not sure you save much be building your lower either.

To me it was all about the novelty of assembling it and getting exactly what I wanted.

I've been looking into building a midlength upper.

Bravo company is selling one fully assembled sans handguards for $530.
Also without BCG or charging handle

Brownells has a similar Daniel Defense setup for $465

I can buy a Daniel Defense mid-length barrel with FSB attached for $320
Upper with FA and DC installed for $120
Delta Ring for $10
Barrel nut for $9
Flash hider for $8
handguard cap for $3
gas tube for $13

Total $483

All three would be similar quality setups...so I could save ~$50 over the Bravo company or spend ~$20 more than the Daniel Defense already set up.

 

[wally]

Not sure you save much be building your lower either.

The bulk of the savings here is avoiding the $100 Federal Excise tax on a complete rifle.

With any of the complete lowers I've seen its pretty easy to save another $50 with the parts and a stripped lower (unless the brand of the lower means a lot to you), even more if they didn't use the exact trigger or stock that you really want.

To me it was all about the novelty of assembling it and getting exactly what I wanted.

I will never argue against doing it and thus having a leg up on maintaining it.

As I always say: "If you've never broken a gun, you just ain't been shooting enough!"

 

[HOOfan_1]

From pricing Colt branded parts I think you would likely spend at least twice as much assembling your own gun as buying a Colt off the shelf...

 

[wally]

From pricing Colt branded parts I think you would likely spend at least twice as much assembling your own gun as buying a Colt off the shelf...

You should do the same exercise for a GM vehicle

IMHO the AR market in the US is like the Chinese manufacturing juggernaut -- contractors branch out on their own when they can make a profit selling directly.

 

[lencac]

Make sure the barrel extension and receiving part of the receiver are completely clean. Now with your finger put an extremely light coat of light machine oil on barrel extension and in the receiver. Make sure the barrel seats fully into the receiver without forcing it.
Using light oil or preferred is antisieze but that will stain anything it touches so care needs to be taken to put it only in the spots you want.
Then screw the barrel nut on and off several times just lightly tightening it against the barrel so the nut and receiver become acquainted with each other.
Then using your approved armorer's barrel nut wrench and a known good torque wrench and starting at 30 ft/lbs. and working up in 5 ft/lb increments watch for one of the barrel nut channels to line-up with the gas tube hole in the receiver.
I use a loose gas tube to check that. Lining up the the delta ring and weld spring and snap-ring is required.
The torque is between 35ft/lb and 80 ft/lb. Ideal is in the 45 to 65 ft/lb range. Note: Once the gas tube is installed the barrel nut cannot come loose.
But absolutely no less than 35 ft/lb and no more than 80 ft/lb. The barrel nut will line-up somewhere in that range. the rest is simple springs, roll-pins and parts.
And make sure you have the ejector port cover door, spring and rod installed before you put the barrel and barrel nut on.

 

[Temp430]

Get a book or two on how to do this. There are several good ones... Walt Kuleck's is the classic.

 

[AlexanderA]

Generally getting the flash hider off is the biggest issue -- barrel in a vice with leather pads, and sometimes, especially with well used rifles, penetrating oil, time to sit, and heat from a propane touch has been required.

This is why I hate crush washers and much prefer the earlier peel washers to index the flash hiders. The last time I had to remove a flash hider, I had to slice the crush washer with a Dremel cutoff wheel in order to relieve the tension enough. With a crush washer, the indexing function is done by the degree of torque, and the people that use them tend to overtorque. With peel washers, you peel layers until you get the exact thickness required.

 

[Arizona_Mike]

I've been lucky with supressors. For supressor use, I put anti-seize on the thread and try to put mine on with no more than 25 ft-lb and can usually add and remove them in the field with a hand wrench holding the gun Suzanne Somers Thighmaster style.

Mike

 

[wally]

This is why I hate crush washers and much prefer the earlier peel washers to index the flash hiders.

I hate crush washers even more now after having had to replace them all with peel washers to use with my Halo suppressor.

 

[Walkalong]

A barrel vise of some sort can be real handy.

 

[B!ngo]

Good idea in general but not always the choice if special needs and occasionally cost get in the way. Recently I built a lower and then added a completed upper that was left handed and in .22LR. This time I just have not found a 300 BLK left handed upper at a reasonable price. So ordered the parts (and the basic tools) and plan to dig in this weekend.
In many cases building does not mean you'll save money, especially when many almost unconsciously upgrade their parts list to levels that they would not have had if they purchased it completed.
B

I've built a lot of ARs.

My modus operandi these days is to build the lower, and buy the complete upper already together...