How does building an AR work?

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EricFox11

Inactive
Hey guys, first post here. I have been reading through some of the "building AR" threads but am still quite confused. I am starting a new job and will have a lot of time and money on my hands without much to do with it, so I would like to build a nice AR (don't own any guns now, other than my Mosin Nagant).

I know the basics are that there is an Upper and a Lower. Is this the complete gun? Or is the barrel assembly/trigger/etc extra pieces to be purchased?

And if I built one from scratch, could I just buy different uppers or something to shoot various bullets depending on the hunting situation, or is each new caliber a completely new AR pretty much.

I guess in the end I could just spend $1000 on a Colt instead of dealing with all of this, what would you guys recommend? I am pretty new to guns.

Or I could get an HK416
 
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Uppers and lower receivers can come in two types:

1. "Stripped" - meanings its just the shell of the upper or lower receiver. You need to then buy all these various components that go IN the receiver.

2. "Completed" - you guessed it, means its good to go out the box

You might stumble upon some variation in the middle of these two distinct categories, but not likely.

For the most part uppers and lowers are somewhat universal. Keep in mind the keyword is MOST. There are exceptions to the rule.

For example DPMS and Armalite do not work together because of slightly different dimensions.

And yes its quite common for for people to have multiple lowers and uppers that can be combined depending on the application.

This is because some calibers are the same as others, the only difference being bullet size or cartridge length.

I think (I could be wrong) that .260 is just a modified .308 cartridge, as an example.
 
ok most of the time you start out with a stripped lower reciever. this is the only part that has to come from a gun store, everything else can be shipped straight to your door. lower parts kits(LPK) normally include the trigger group but not always, so you need to be sure to verify before you get it. for the most part the lower parts kit is all the little pieces that hold the gun together. other pieces of the "lower half" is the buffer tube, recoil spring, buffer, and pistol grip(sometimes included with LPK).

upper halves are normally fully assembled but if you really want to build from scratch you will need a vice and a few specialty tools. for the most part many companies sell upper halves that are exactly what you are looking for anyway and removes the need to buy individual barrels, recievers, bolt carrier groups(BCG), dust cover(not found on all ARs), forwardassist(not found on all ARs), charging handle, handguards, gas block/front sight post, gas tube and flash hider.

a few exceptions are some companies sell upper halves that do not include the BCG. a good company to start with is palmetto state armory. their complete uppers are very high quality and very affordable and the sell lower parts kits that include everything from buttstock to mag release.

when it comes to actually assembling it, youtube has a large amount of instructional videos.
 
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and look at all the picture threads to see exactly what you want, they usually do a pretty good job at describing each part

one of the best reasons to build your own is that it is what you want instead of buying a package deal and replacing half of everything because it isn't right for you

there are 2 different types of buttstocks, carbine (shorter, more compact) and rifle (longer better for longer range shooting)

each has it's own length of tube, buffer and spring

plus commercial and mil-spec diameters, make sure you get all the same type so they fit together

and there are different lengths of gas systems, carbine, midlength and rifle, but that isn't so important right now

the choices are limitless and that is most of the fun


and as posted above they have different calibers of uppers you can put on the same lower and make the rifle more versatile for any type of use you need.

there are lots of brands and most are of good quality, before you buy just do a search and there will be many message board threads touting or razzing them all:D

have fun and ask lots of questions, don't waste money
 
Upper receiver
Barrel
Barrel Nut
D-Ring
Gas tube
Gas block
Flash suppressor
Hand guard
Hand guard end plate
Bolt carrier group
Charging handle
Front sight
Rear sight
Sling Swivel parts

Lower receiver
Lower receiver parts kit (includes trigger, springs, pins, levers, pistol grip)
Buffer tube
Action spring
Recoil buffer
Butt stock
Castle nut
Sling Swivel parts

There are two types of hand guards - fixed and floating, and this will determine some of the upper parts required.

There are two types of stocks - fixed and adjustable, and this will determine the buffer tube, buffer and action spring required.

My advice is to go to Brownell's and use their Build an AR-15 feature on their web site.

Oh yeah, chances are you're going to need to spend $300 on tools that you probably don't already have.

Building an AR-15 isn't hard, but you have to consider that if you do it wrong, you could hurt yourself and/or others. That being said...

If it's your first AR-15, buy an inexpensive one (the S&W M&P15 Sport is a a good choice), and modify it. Build a whole new upper for it, replace the trigger with something better, replace BCG/buffer/spring. This will give you the same feeling as building one yourself, but you'll be able to put the factory parts back in it if you screw something up.

Alternatively, you could just go out and purchase a complete gun, and a Colt is a good (if not kinda pricey) choice. Smith&Wesson is also a good choice. the only problem with cookie-cutter guns (my term for guns from Colt, S&W, etc) is that they have very few optional configurations to choose from. If you want more options to choose from, go with Spike's, Bravo Company, Palmetto State Armory, or someplace like that.
 
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I strongly recommend that for your first AR at least, you buy a complete rifle. I built my first, and I wished I hadn't bothered. It looks like you're going to save money, but you're not really - unless you sacrifice quality. If you can afford a good rifle, there's no point in skimping.

If you want a rifle that's equal in quality to the Colt you mentioned, you're going to end up spending close to the same price no matter how you do it - not to mention the hassle of building it, and the hassle of having separate warranties for various parts.

For example, I bought my rifle as a pre-assembled upper, and a kit of parts for the lower. The upper was perfect, but the trigger parts I got were terrible. They did not function reliably, making them dangerous and potentially illegal, but even if they had worked correctly it was still a terrible trigger. This is not exceptional with the cheaper kits. The dealer was willing to replace the faulty trigger - but that still represented a huge risk for me, and the best case scenario was that I would up with an apparently reliable but lousy trigger. So I had to go out and buy an expensive one anyway. I also had to buy sights, a stock wrench, magazines. So when I add it all up, I've spend well over $400 more than the cost of the complete upper + complete lower, which I naively thought was going to be more or less a complete rifle! Add to that the fact that I did not have a working rifle until most of these things were sorted out.

Of course you may not be as naive as me but it's easy to be caught out this way when it's your first AR!
 
I've only started to consider an AR. My last visit to a gun show revealed tons of AR lowers available.

It is the lower that requires all the paperwork and such. From a gunshow, there is no paperwork if you get it from a private dude.

I was thinking of getting an lower from the gun show, and then getting a super cool upper online... allowing me to skip the FFL crap.

It would be funny to get a Plum Crazy lower and then a sweet Daniel Defense upper!
 
bfskinnerpunk said:
From a gunshow, there is no paperwork if you get it from a private dude.
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While that may be so in your state, it does not hold true for all states. In some states it would be a felony to buy or sell a firearm (the lower) without doing the transfer through an FFL.
 
I would not recommend "building" an upper from scratch for a beginner. In most of the cases I've seen, the cost of the individual parts ends up being as much or more than a complete upper put together by someone who knows what he's doing and has the proper tools to do it.
Some smart shopping might turn up a complete rifle cheaper than the parts but shipping and FFL fees might change that.
If buying a "complete upper", make 100% sure the bolt carrier group(bolt, carrier,and charge handle) is included. Some sellers will advertise the upper as complete , then in the fine print say"use your own BCG". I've never had a problem adding a new BCG to a new or like new upper but you don't want to think you're getting a good deal only to find you're out another $125 for a BCG.
 
So much good information guys, thanks!!!

Many things have been cleared up. So let me run this by you all. Honestly the money is too big of a deal to me, and I am a huge perfectionist OCD person and take care of everything I have and always make sure it is working correctly. So at 23 years old, I would probably be better off just buying a good Colt and spending a little extra money. I like an AR that looks like the Colt Model LE6940. Having the rail system instead of the polymer cylinder thing is better IMO.

That being said, can I buy new uppers and accessories for the Colt to customize it?

One thing I would REALLY like to do, is have a gun that shot a .223 due to the price and practicality of the ammo, but be able to convert it up to a .308 or something in that range for going hog hunting etc. Is this possible with a Colt, or any .223 gun I buy for that matter?
 
Not really, there are a few odd examples but AR15's dont have a big enough magwell to feed something like .308. You can get other .30 caliber or intermediate rounds though that work well for hunting.

With my friends I use the term "assembling" an AR. Theres no real building and everything goes together like legos. Theres no real fitting or anything like a 1911 or m14.

If you can change the oil in a car, you can probably assemble an AR.
 
So what other bigger round could I buy to just drop in the .223 AR and it would work? And would it use the same clip or not?

I guess I'm just going to purchase an AR and then customize it myself. The only thing I don't know is, should I buy a Colt with the rail system for around $1500 or should I buy a cheaper AR (like $700) and then put a rail system on that...no idea how much the rail system would be though.
 
Just buy a Rock River or S&W. No sense in paying all that extra just for the Colt name.
Personally I love my Rock Rivers. I have 12 of them in various configurations in 5.56, 6.8 SPC, .458socom, and .308.
As far as additional caliber uppers on the AR15 lower, there are many, but it is limited to the overall length of the round being no greater that a .223/5,56. A .308 will not work period and neither will any similar length calibers. The upper receiver won't even mate to the lower because they are much bigger.

A couple that I know of that will work on your AR-15 lower:
6.8 SPC
.300 Blackout (becoming very popular now)
.450 Bushmaster
.458 Socom
.50 Beowulf
 
So what other bigger round could I buy to just drop in the .223 AR and it would work? And would it use the same clip or not?
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ok well before everyone else gets all OCD about it, it's a magazine, not a clip. clips do not fully attach to a gun but rather temporarily store ammo for ease of loading.

with that said. a lot of the larger rounds for AR15s are based off the 223/5.56 casing so rounds like the 300 blackout, 300 whisper, and 300 fireball work fine with the standard AR magazines. other calibers such as 458 socom, 5.45x39, 7.62x39, 6.5 grendel, and 6.8 SPC(I could be wrong with this one) all need their own mags. spikes makes a 7.62x40 round but everything is incredibly expensive from gun parts to ammo. I've heard rumors of a 243x45 which would be a decent medium between 223 and 6.8SPC. among all the specialty rounds 6.8 is probably the most prolific since it one of the few that you can actually buy from the store instead of being forced to rely completely on reloading. I know a lot of guys hunt hogs solely with 223 so just about any of the larger cal bullets would work very well.

if you absolutely have to have the best setup for hunting I would trust 6.8SPC as a decently capable deer rifle so hogs would be a no brainer with it.
 
You could build a Del-Ton. And for $1000 it would be fairly well tricked out. The uppers ship fully assembled and head spaced.

You order a rifle kit, it comes with everything except the stripped lower.

Then you order the stripped lower.
 
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