AR-15 build questions


Chris taylor
March 26, 2010, 05:46 AM
Hey guys, just joined the forum so still not framiliar with the posting rules...(bear with me!) Anyways Ive been looking at building a simple, no frills, battle ready AR for awhile and have several questions... First, I would like to know if ATI lowers will function as well any others. Secondly, would 1:7 or 1:9 rifling be better for average accuracy with 55gr ammo. And, lastly would like to know if I should order the chrome lined barrel due to fouling issues with the ball powder... Any answers will be greatly appreciated! -Chris-

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March 26, 2010, 07:48 AM
Welcome Chris,

Can't tell you on the ATI son just bought at a gun show,
a Colt 20" HBAR upper, complete for 300.00 an a complete DPMS lower
with folding stock for 199.00. My Colt HBAR has 1/9 twist, an his is 1/7.
I asked on this forum about the twists...seems both will shoot 55 gr.
But many committed that after 100 yards with the 1/7 you want a heavier
bullet for better accuracy....1/9 twist 52gr to 62gr. an 1/7 62gr an up seems
good...some results an opnions vary..but this is what I learned.
Chrome lined last longer, stays cleaner...but I believe the hard core target
shooters in matches don't like the chrome line barrels....not first hand experience,
just what I've learned from others

March 26, 2010, 09:11 AM
A chrome lined barrel is more durable and more corrosion resistant, so I would prefer chrome lining on anything but an all-out target rifle with a match chamber and whatnot.

Also look for a 5.56x45mm chamber, not a .223 chamber; you can shoot .223 in a 5.56 chamber, but the other way around (5.56 in a .223 chamber) is less advisable due to pressure issues.

March 26, 2010, 10:17 AM
Ball powder was an issue in 1966, it's no longer used, and wasn't supposed to be anyway.

Reviews on ATI lowers might be found on,, etc. In general, most lowers right now are a commodity item, they are mostly all good to go. Price differences seem to exist by what roll mark is on them more than serious differences or defects.

As most of the forgings come out of less than half a dozen shops, and only about a dozen actually machine, the majority of uppers and lowers are basically sourced from this small pool of actual makers. Most brands don't actually manufacture, they just assemble.

Chrome lined is spec for auto/burst military use to reduce throat erosion, it's not necessary for a semi auto, and doesn't give a precision rifle barrel. Plating back to a consistent dimension internally and keeping it within .0010 is pretty hard to do. Button rifled barrels frequently gauged with dips and valleys of up to .0030, the combination makes most chrome lined mispec barrels average 2MOA, which is good enough for a hit in combat to the effective limits of the caliber.

For twist, some will insist on 1:7, it really depends on the bullet weight you will consistently use, not an arbitrary military standard.

March 26, 2010, 11:09 AM
Some thoughts on building an AR:

March 26, 2010, 11:27 AM
Welcome Chris,

While I have no first hand knowledge on ATI receivers, I did some asking around and some quick web searching and the consensus is that they are as GTG as any other basic MILSPEC lower.

The lower receiver is functionally the most fungible of the AR component. As long as it’s in spec you should be fine.

As far as the upper receiver, that’s where you should concentrate your money to make sure you have a good rifle. Get a quality upper with as good a bolt carrier group as you can.

The following are well regarded for quality especially for the price.

Bravo Company

Spikes Tactical

DSA is a well regarded manufacturer of things FAL that has recently gotten into the AR game at a very competitive price point.

As to the barrel coatings: MILSPEC is chrome lined. Unless you are putting together a precision long rage varmint rig I would get this. Another choice is a “nitrided” or “nitro carburized” barrel. This is a form of case hardening similar to what is done to Glock slides. In wear and corrosion resistance it is in many ways superior to chrome lining and has less negative effect on accuracy. DSA offers nitrided barrels in their complete upper assemblies. Several high end barrel manufactures are using this process as well.

Unless you have a complete lower you are going to have to add a lower parts kit (“LPK”) Most major manufacturer’s kits should do fine. I have used Double Star, Rock River and Daniel Defense and they all worked great.

Next you will need a stock, buffer and spring. The combinations of which can be confusing. The 2 basic choices are: do you want a fixed stock or collapsible one?

If you use a collapsible stock there are 2 kinds of receiver extension (AKA “buffer tube”) MILSPEC and commercial. They are dimensionally and structurally different. Get the MILSPEC, it’s stronger and there are more stocks that will fit that size.

Go to or for tons of information on all things AR. Both sites have sections on building your own what to do and what to avoid

A few before and after pictures of an AR assembly I recently completed can be found here

March 26, 2010, 12:34 PM
Unless there's any chance you may want to buy a complete rifle (maybe because you don't want to invest in the tools to build one AR - definitely be aware of the tools you'll need before starting a build), I would go ahead and get a stripped lower receiver with the roll mark you like best within your budget. As described above it's pretty hard to go wrong with the lower so you might as well get the FFL part out of the way.

Then research the options for the rest of the AR (good points above) and finish the lower with the lower parts kit and buttstock of your choice. After that of course finalize your decisions on the upper and complete the build. An assembled upper is a popular choice but be sure you get it to YOUR specs.

For a first build, taking three or four months of research before purchasing everything is a good idea. And it allows you to save up for the next step and put your money where it really matters. This is what I did and I'm very happy with how my AR turned out.

March 26, 2010, 12:47 PM
Winchester 748 Ball Powder is one of the best in my personal experience.

P-Mags will relieve you of the need for M-4 feedramps.

1-7" twist will get you past 68 grain bullets

my 1-9" will do up to 65 grain hunting bullets at .75" 100 yds all day long

March 26, 2010, 04:13 PM
You might have to buy specialty tools for assembling an upper, but for a stripped lower, LPK, etc; I only purchased a $6 stock wrench. I used a set of punches I had in my tool box, some vice grips, and that was about it.

A complete upper will simplify things while allowing you to mix & match other areas (stock, pistol grip, etc).


March 27, 2010, 01:03 AM
Read up on m4carbine and for a wealth of information. A little more chaff on ar15 in my opinion.

Take your time and do your homework. I'm on my second rifle now. Built the lower and bought the upper complete. I don't regret my first rifle but if I had done more research I would not have bought that configuration for my wants/needs.

ATI lower should be fine.

Chrome lined on a "fighting" gun is a plus

As far as twist go you should be fine on either for 55 gr pills but personally I would go for the 1:7 for the better stabilization of 68+ pills.

Buy once and cry once.

Chris taylor
March 27, 2010, 01:33 AM
Well thanks for all the help guys! And regarding the stripped lower, Im actually settling for an ATI lower with an A2 stock from a local shop for 220. And even though it will be used for shtf situations,I thing im going with the 20" 1:9 (shooting 55gr wolf will be stable enough) del-ton upper with an A2 handle and all bare bore... I have some work lined out for me by my dad, so it looks like were on the gravy train with biscuit wheels! Pics should be up in the next couple weeks. Figure I'll get the lower first... -Chris-

March 27, 2010, 10:06 AM
You did say "battle ready". I'd skip the Delton, it's more of a plinker than a battle ready Ar. We have one that has a barrel that looks to be made by a Dewalt grinder. Very bad finish inside the barrel.

For at little bit extra, you can get a much better upper. A Stag 20" is upper decent. A BCM 20" is Jellybeans! 1/9 is ok, 1/7 is a better defensive rifle. LMT, Colt, Sabre Defense, etc all make good uppers.

Barrel finish is key. A Chrome lined finish is an absolute must have. The Chrome is slick and aids feeding and extraction. And it sheds carbon better. Only a SS target barrel can go without. And thats only if is finished well in the chamber.

Most likely your lower is fine. As long as everything is straight, the lower deosn't do much.

March 27, 2010, 10:44 AM
I thing im going with the 20" 1:9 (shooting 55gr wolf will be stable enough)

Why fool around with the 1/9 barrel?

Both my ARs have 1/7 twist barrels. They shoot XM193 ok (2MOA groups) and 75gr PPU very nicely (1.1-1.25MOA groups) too. I've also shot 50gr varmint loads with no problems from the same barrels. BSW

March 27, 2010, 11:02 AM
You did say "battle ready". I'd skip the Delton, it's more of a plinker than a battle ready Ar.

+a million.

However, the biggest factor for "battle readiness" is going to be the bolt carrier group. With a 20" barrel you don't have to worry about the holy 5-coil spring with black insert, but gas key staking is still a factor, as are shot peening, testing, and inspection. Get a better brand of upper, and a BCM, LMT, or Colt bolt carrier group.

March 27, 2010, 06:09 PM
Here, This was posted by Jeep297 over at This is great info and pricing on a top tier AR.

**Update** Great review on the upper in the following links thanks to 87GN and Stickman: (87GN) (Stickman)

Since so many people around here are fairly new and keep asking what the best/cheapest deal out there is, I thought I would post this to help them out. For a little more than $700, you can buy an extremely high quality rifle, including BUIS, that easily outclasses anything near it's price range. Look at the specs below and you will see this is definitely the best deal out there right now by a wide margin. Specs include:

M4 feed ramps
Chrome lined barrel
Magnetic particle testing on every barrel
F marked front site (Phosphate finished under)
1/7 twist
4150 barrel
5.56 chamber
Auto BCG properly staked w/ MP tested bolt
ST-T2 buffer
Milspec tube for more stock options

Here are the links:

Complete Spikes Upper $475

Complete Lower $180 (now $200)––-DSZM4R2/productinfo/DSZM4R2/

Rear BUIS $55 (I personally like Troy or KAC sights more but these work well and are cheaper)

** You can also keep the entire rifle Spikes for only $759 (type arfcom at checkout for 5% discount)

Chris taylor
March 29, 2010, 04:48 AM
Awesome! And thanks for the links. Well looks like i may be changing the upper then... Im thinking something like 1:7, with a 'shiny' bore and a colt bolt group? and the only reason why i wouldnt be shooting any 'horse pills' is cash flow... i'd prefer to double tap and just use wolf! And sorry if I sound like a cheap bastich... but im still a minor so theres not a lot of padding in my wallet at the moment. Anyways the lower should be in my hands in a few weeks! :Big fat grin: -Chris-

March 29, 2010, 05:13 AM
Chris... really take a look at the BCM uppers. A 20 inch upper with one of their auto BCG, a charging handle and some handguards is around 650 bucks. Add that to your lower for a great "battle ready" rifle.

Truthfully that Spikes Tactical rifle that steven58 linked to is a pretty good deal. I dont have any experience with their products, but many seem to really like them.

Chris taylor
March 29, 2010, 05:24 AM
Hey thanks Grunt! I Googled them but all I found was DC shoes!... lol anyways i figured i'd buy a lower now before the prices go up, and even if i keep it 3-4 months before i buy an upper... that just gives me even more time to save up for the best...

March 29, 2010, 05:56 AM
Here is the BCM website.

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