First AR-15 Upper Build Questions

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BigNate
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First AR-15 Upper Build Questions

#1

Post by BigNate »

OK folks - I've assembled AR-15 lowers from a bare lower to functioning but never an upper. Me and Youtube are getting ready to work together to build an upper from the ground up. I'm hoping folks here might take a look at my list and assumptions and set me straight if I'm headed down the wrong path...

Stuff I think I'll need... I'm excluding sights and accessories as I'm not worried about them - I'll figure that stuff out after. I'm listing things that I think I'll need to assemble a functional upper that can feed and fire rounds. What am I missing?

Parts
  • Barrel
  • Barrel Nut
  • Barrel Nut Shims
  • Bolt Carrier Group
  • Ejection Port Cover
  • Forward Assist and Spring (assuming that I choose an upper receiver that needs one)
  • Gas Block (adjustable - with pin)
  • Gas Tube
  • Handguard
  • Muzzle Device
  • Upper Receiver (bare)
Tools
  • AR-15 Upper Lapping Tool (I get that this is not "required" but I figure if I'm going to do it I might as well do it right)
  • AR-15 Armorer's tool - for the muzzle device and who knows what else
  • Barrel Nut Wrench (specific to the type of nut that I'll use - might get fancy - not sure)
  • Basic Bench Block
  • Bench Vice
  • Feeler gauges (to gap the gas block)
  • Mallet / Hammer (to set the pin for the gas tube / block)
  • Punch Set (for use with the mallet above)
  • Torque Wrench (to torque the barrel nut - standard homeowner quality click type torque-wrench will do - yes?)
  • Upper Receiver Vice Block
Supplies
  • Blue Locktite
  • Gun Grease
Thanks in advance...


QuietM4
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Re: First AR-15 Upper Build Questions

#2

Post by QuietM4 »

It's a good list, but some of that stuff you won't need;

Barrel nut shims - only needed if the forend/rail you buy needs them...and then it should come with the rail.

Gas Block with pin - DONT get a gas block that required a taper pin...this will cause you a big headache. Look for a barrel that is pre-dimpled for set screws, and get a gas block with set screws.

Upper lapping tool - only needed if you are trying to build an ultra accurate rifle...if it's just a standard M4 build, don't bother wasting your time.

Barrel nut wrench - Magpul makes a nice armorer's wrench.

Bench block - Magpul also makes a nice bench block, the BEV Block.

Feeler guages - You don't need these at all.

Torque wrench - over kill, not really needed.

As long as you are buying tools, buy once cry once.
https://www.realavid.com/product/ar15-a ... aster-kit/
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BigNate
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Re: First AR-15 Upper Build Questions

#3

Post by BigNate »

Thanks sir... I already have most of the tool list stuff - OK - all of it other than the barrel nut wrench, the lapping tool, and the vice blocks... Your reference to the Magpul armorers wrench made me think - and I believe I just figured out what the square hole in that wrench right next to the barrel nut end of the wrench is for... I had been wondering. Re the lapping tool - this first build will be a short barrel upper - not a precision rifle - but the next one will be a precision piece. I figured I'd get the lapping tool now so I can practice on the one that won't need it - and the next one won't be my first pass... :-)

As to the pin - I was referring to the gas-tube pin - noting that it sounds like they often don't come with one...

A couple of questions re the gas block stuff... I'm looking at a few lists on the interwebs regarding adjustable gas blocks - because this will be a short barrel upper that will eventually get a suppressor and I want to be able to adjust for subsonic suppressed and supersonic loads. I seem to find the Superlative Arms block well up most lists and referenced as the winner for suppressed stuff so I'm leaning their way. They list it as a "clamp on" device - and while I can't find install instructions I don't see any reference to a set screw. It appears to simply clamp to the barrel. Thoughts on these?

I presume that when you talk about a barrel that is pre-dimpled for set screws the purpose is to specifically index the gas block to the gas hole in the barrel. Some of the stuff that I'd seen indicated that you needed to clearance the inboard edge of the gas block (the first part to go over the barrel when installing) from the ridge by a few thousandths (I think I saw 0.020 - 0.035) - thus the feeler gauges. I've watched a few more videos where they don't worry about this - so I'm guessing it is something more specific to us OCD types? I'm also guessing that the dimpled barrel and set screw approach fixes this - but that it's not available if I go with the clamp on block from Superlative. Overkill?

Thanks again for the good info!
QuietM4 wrote: November 2nd, 2022, 7:18 pm It's a good list, but some of that stuff you won't need;

Barrel nut shims - only needed if the forend/rail you buy needs them...and then it should come with the rail.

Gas Block with pin - DONT get a gas block that required a taper pin...this will cause you a big headache. Look for a barrel that is pre-dimpled for set screws, and get a gas block with set screws.

Upper lapping tool - only needed if you are trying to build an ultra accurate rifle...if it's just a standard M4 build, don't bother wasting your time.

Barrel nut wrench - Magpul makes a nice armorer's wrench.

Bench block - Magpul also makes a nice bench block, the BEV Block.

Feeler guages - You don't need these at all.

Torque wrench - over kill, not really needed.

As long as you are buying tools, buy once cry once.
https://www.realavid.com/product/ar15-a ... aster-kit/
QuietM4
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Re: First AR-15 Upper Build Questions

#4

Post by QuietM4 »

The SA gas block is a nice one, but don’t get the clamp on version…you just add more screws that could possibly break or come loose. The standard model that slips over the barrel is better. Most gas blocks will include the gas tube pin, or the gas tube you buy will include it. Gapping the gas block from the barrel shoulder is completely unnecessary.
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BigNate
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Re: First AR-15 Upper Build Questions

#5

Post by BigNate »

Thanks sir... I see now that they have the other type. Makes sense to me...
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xerts1191
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Re: First AR-15 Upper Build Questions

#6

Post by xerts1191 »

Pics when finished Nate
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BigNate
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Re: First AR-15 Upper Build Questions

#7

Post by BigNate »

You bet. It's going to be a bit... just starting to build the parts list - expect to start ordering parts next week.
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