AR15 Build Question...


December 30, 2012, 12:10 AM
This is the first ever build I've attempted.

I picked up my lower today and ordered my LPK last night (Daniel Defense...I knew I would be picking up lower today). Well, I got to thinking that I really want to assemble every part on my rifle, so I started looking at Uppers an Stocks and what not. The reason I want to assemble every piece myself, is because I really want to know all the inner workings of my rifle. Mainly because, in case something breaks, then I will know how to disassemble it and repair it.

My dilemma comes in, is this a smart thing to do to completely assemble it myself or should I just buy a completed upper with barrel?

Any and all help and advice much appreciated.

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December 30, 2012, 12:11 AM
Oh and I plan on doing a flat top M4 barrel and upper.

Blackwater Red
December 30, 2012, 12:58 AM
Brownells has an excellent tutorial on AR-15 assembly. Go to and click the link on AR-15.

December 30, 2012, 01:01 AM
Hmmm I didn't find that earlier. I'll have to go back. I did find there parts list though.

December 30, 2012, 01:07 AM
watch a video of assembly so you know how they go together, then just buy a complete upper so you don't spend the money on barrel wrenches, action blocks headspace gauges etc that you will only use once.

just my 2 cents.

December 30, 2012, 01:13 AM
The headspace gauge could come in handy, since I reload.

December 30, 2012, 11:11 AM
There's a lot of folks in the AR community who don't bother w/ action blocks & headspace gauges. An action wrench is absolutely necessary b/c of the specialized bbl nut, & castle nut if you're building a carbine. If you really want to be perfect, you'll need a torque wrench - there will be a 1/4" slot on nearly any action wrench to use a torque wrench. has a wealth of assembly information - just don't ask "which one should I get?" Their motto is "Get both!" You'll use the action wrench again & again.

December 30, 2012, 12:05 PM
Awesome. I'll have to check that site out.

December 30, 2012, 12:14 PM
Why headspace gauge? You can't adjust it, unless you ream it. That's done by the barrel maker. If it's in factory spec, then it's correct.

December 30, 2012, 01:41 PM
Although you cannot (easily) adjust headspace on an AR, I do use gages to verify that the manufacturer got it right.

January 3, 2013, 09:42 AM
Where is AR15 link on Brownells? I only found the AR15 Assembly template.

January 3, 2013, 09:55 AM
I just got myself two of the new dedicated AR15 catalogs from Brownells a couple of days ago, I'm waiting for the new master and 1911 catalogs.

January 3, 2013, 02:47 PM
My gut sense: If you want the nerdy fun of building it yourself, go for it... I have built all my own lowers and toyed with the idea of building the uppers, too.

However, when push came to shove, the cost of components and tools amounted to just about the same cost as a comparable, complete upper from a known manufacturer (especially if you factor in time). As far as I can tell, building you own upper benefits *objectively* benefits two kinds of people:

Those who have very, very specific wants and are willing to piece things together appropriately... "I really want a SuperFine brand barrel, a PlentyAwesome BCG, and a WickedCool forged golden upper."
Those who have more general wants and are willing to patiently wait for the best buys to crop up... "I want a mil-profile barrel, a reputable BCG, and a decent mil-spec upper."

Subjectively, building your own seems like a whole ton of fun! :)

January 3, 2013, 02:58 PM
The headspace gauge could come in handy, since I reload.The headspace gage you use to check a rifles headspace has nothing at all to do with reloading.

There is no other use for it except checking rifle headspace in the gun.

This is a rifle headspace gage:

This is a reloading case headspace gage:

January 3, 2013, 11:46 PM
here you go. this guy builds a whole gun for you.

google and youtube are your friends. :)

January 4, 2013, 02:03 AM
Building a lower yourself gives a couple of advantages - 1, you save a little on the excise tax, as you're only paying it on a small piece of aluminum, not a $600, er, $2000 rifle. 2nd, if one will forgo putting a buttstock on it for a bit, you now have built an AR pistol. True, it may be a 24" bbl 6.5mm Grendel pistol w/ a full length buffer tube, but under the 1934 GCA, if it doesn't have a buttstock & is a Title 1 firearm, then it's a pistol. Thus, you have gone Other > Pistol, and can now go Pistol > Rifle > Pistol. The only real disadvantage that I can see, is you can't buy a stripped lower from a FFL until you're 21.

If you build your own upper to no particular design, you can buy inexpensive parts as they come along - why I own a 16" bull bbl carbine w/ a dissy sight tower & a carbine gas system - & carbine handguards. Looks odd, but it works. Before that, it was a 16" bull bbl straight-pull bolt action pistol.

January 4, 2013, 04:20 AM
OP, if you come across a decent deal on a complete assembled upper that you like, go for it and buy if its within your budget. You can always modify/change/upgrade anything u want.

One of the minor downsides I want to point out with "building" AR's is the availability of parts, or lack thereof esp with the current state of things. I currently have 2 AR builds that are coming along verrrry slowly because the parts I want/need are either out of stock or too expensive. Buying a complete upper/lower receiver bypasses this issue.

Not a big deal if you are patient and willing to wait it out, but it can get kinda annoying sometimes if you have a build that takes months due to lack of parts; for me anyway. I sometimes hate seeing 2 incomplete AR's sitting on my work table because some parts are unavailable.

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