What makes a good AR?

[Scratch]

I’ll admit it… I’m still fairly new to the AR15 platform of rifles. But I’m on my 4th now for me, and am starting to have some questions. I’ve also helped my brother with a build, and one customer with a build too. And some I wouldn’t consider “builds’ since they were just pinning a complete upper onto a complete lower.

All 6 of the builds I’ve done started life as a stripped receiver. 3 were PSA, one NFA, one Aero, and one Spikes.

If it wasn’t for the rollmark, I couldn’t tell them apart. We put CMMG, and PSA build kits in each of them, and various stocks like Magpuls PRS, MOE, CTR, PSA’s Classic, and even GMG classic stocks. Using both Mil-Spec and Commercial. I’ve done aftermarket charging handles like BCM’s, and a couple different brands of BCG’s like PSA, CMMG, and RRA.

My question doesn’t relate really to aftermarket add on’s though, what I’m wondering is what makes a good AR… a good AR?

I don’t want to talk about parts that are easily changed, in my mind, these include:
Lower parts kits
Stocks
Forends
Sights/optics
Charging handles
BCG’s
Muzzle brakes/ flash supressors

Which leaves:
Lower receivers
Upper receivers
Barrels

For now…Let’s not get into the whole piston/DI system and focus only on the more common DI.

Let’s start with stripped lowers. Is there really a difference in them? I’ve seen them (before the craziness…) from 49.00 (PSA) to 400.00.
From the few that I’ve seen, they seem to be perfect fit with all other uppers I’ve owned. (I’ve tried them all to see if I could find one that didn’t fit) and I’ve never had a LPK that had any problem with fitment of any pins or anything either.

Uppers. To be honest, I’ve never did a complete build from a stripped upper, with an upper parts kit, but I gotta imagine it’s the same as the lowers. I could be wrong, but it sure seems the hardest part about putting an upper together is lining up the gas tube, and using a torque wrench.

The barrel is one of the only things “I think” that can make or break an AR15. Please help me understand where I must be wrong on this.
If the barrel is made of poor quality steel, has poor rifling, bad machining, bent, or not torqued to specs… I can see that causing a major problem in accuracy and possibly reliability.

The other thing I think could be a problem is the bolt and carrier. More specifically the bolt since it’s responsible for ejection and extraction. Let’s assume most carriers are staked properly, if it is… where else can you go wrong?

So…. And this is where I would like your input… Let’s say you bought a complete rifle from one of the big expensive names like BCM, Daniel Defense, Colt etc…
If you thought that was the very best rifle out there, couldn’t you take the barrel off it, or if you were worried about the torque specs, take the entire upper off it, and slap it on any lower and have just as good of a rifle?

So in my mind, it’s the barrel, Bolt and possibly the carrier that’s important in a build. How wrong am I here?

[ijosef]

I thought it was the amount of tacticool stuff you have hanging off it.

Seriously though, I want to know the same. I've never owned an AR but would like to someday (if the panic subsides and there's no new regulation) and this would be good information.

So, I have added nothing of value to this conversation.

[curly2k3]

Quality barrels paired with good ammo help a lot, as do fitment between upper and lower. If it's all together tight and operates flawlessly it'll typically be a solid starting point for a great rifle, once you start optimizing it for a task (stock, forend, ect...) is when you can start evolving it into an even better and more purpose driven rifle. A great carbine or SBR wouldn't be the best for precision shots, or vise versa.

[promod1385]

Better barrels will give good accuracy, bolts will make it strike and eject as they should , good magazines and ammo are necessary.

[MaxCarnage]

good magazines and ammo are necessary.

This is and has been very difficult to locate, at a decent price.

[The Lance]

Quality of barrel, the material its made out of is the biggest factor.

Magnetic particle testing, etc is not that important but it separates subpar companies from the bcm, colt and Daniel defenses of the world.

The chrome lining is 2nd most important, just because something is chromed lined doesn't mean it is done evenly or has mil-spec thickness of chrome, which in tactical, longevity and accuracy matters.

A cold hammer forged 4150 Chrome molybdenum vanadium barrel is probably the best accurate and long lasting barrel one can get.

Bolt carrier group is 3rd. The proper weight and rear shape of a full auto m16 bcg is always better then the AR15 bcg as the platform was designed to run better with a more balanced bcg. Proper staking of the gas key, mpi testing isn't as important here but the finish of it can matter as a nickel boron coated bcg would run move reliably as it's a self lubricating material.

If that was TLDR
barrel, and bcg
I would trust any lower and upper combo with my life if it has those two things properly manufactured.

[FJ540]

http://www.300blktalk.com/forum/viewtop ... 28&t=81802

This is why you really want forged parts. Granted, they're mainly designed to sustain being used as a club, but the other part of the intention was to prevent the shooter from being injured in a KABOOM.

Proper materials and processing is where the quality differences come into play once you get beyond the dimensional/tolerance issues.

The BC weight balance concept is laughable. There's no way a lighter bolt carrier would cause reliability issues. If that was the case JP wouldn't sell a light weight carrier for a higher price. The additional mass does help slow the bolt down to reduce recoil impulses (and restrain rpm from going too fast) in high fire rates and with shorter barrels, but beyond that it's hardly a point worth noting other than you will never activate a full auto sear without that additional section of metal on the semi carrier. In fact, the extra weight is added to prevent excessive battering of the rifles internals from slamming into the extension and overpowering the spring - it has nothing to do with functional reliability or some mythical desired direction for brass to be ejected.

[The Lance]

You contradicted yourself in the last part. The extra section and weight is to prevent the system from tearing itself apart. So how does that not make it run more reliably? Of course the bcg and barrel ar the most important parts of an AR. It's two parts that do all the work.

Any forged 7075 aluminum upper and lower made to spec will work. Regardless of who makes it.

Y

[FJ540]

Running reliably on wolf ammo would be better with a lighter reciprocating mass. Running long term with full nato loads you'd want a bit more weight if you have a short gas system. Too much weight and it'll short stroke. You're trying to put words where they didn't exist.

[Hmac]

Quality barrels paired with good ammo help a lot, as do fitment between upper and lower. If it's all together tight and operates flawlessly it'll typically be a solid starting point for a great rifle, once you start optimizing it for a task (stock, forend, ect...) is when you can start evolving it into an even better and more purpose driven rifle. A great carbine or SBR wouldn't be the best for precision shots, or vise versa.

The fit between upper and lower is a nice cosmetic feature IMHO but has no bearing on the function or accuracy of an AR.

[TTS]

The question is a bit broad, but in general a good AR has appropriate components for its desired use; i.e., LE/Home Defense, 3Gun, Varmit, etc.

Then you have the build quality; i.e., gas port size, gas key staking, castle nut staking, barrel torque, etc.

If you are planning on using your AR for self defense, you should be picky about your components and build quality. If it is a range toy, it is not as crucial to have a dead nuts reliable AR.

[Dave Timm]

I'd argue that a melonite treated barrel is tougher and will last longer then hard chrome. I'm biased because we use melonite barrels but I've been very I pressed with our barrels. Melonite is great not only for its great corrosion resistance, but also offers a harder hardness level the chrome and is more uniform and doesn't have deficiencies that can be found with chrome lining.

Things to look for in a quality ar, any ar.
Receivers, look for quality forged receivers made from 7075 aluminum, with type III hard anodizing. Quality billet uppers are ok as well.
Receiver extension, aka buffer tube, 7075 as well, cheaper ones are softer 60 series aluminum.
Bolt carrier, made from 8620 steel, shrouded and I prefer full auto with proper staking in the case of DI or one piece with piston.
Bolt made from 158 carpenter steel, MPI, proper extractor spring and insert, also possibly o ring.
Barrel 4150 CroMoV steel, cheaper barrels use 4140 or cheaper, Stainless is also ok but a different beast. Again I prefer melonite over chrome lining for my barrels.

That's the start of the "core" then you have to look at assembly, other components, torque, and the list goes on and on.
Some people get really wrapped up in brands and "mil spec". That's great and I totally understand that. Keep in mind mil spec can be a ceiling or the floor. For example, enhancements and improvements have been made to and beyond mil spec like melonite, mid length gas system, extractor components, adjustable gas blocks, piston systems if you go that route, new buffer systems etc etc etc. so don't get wrapped up in mil spec. Also that term is thrown around so much that sometimes stuff isn't even though they say it is. I can't tell you how many rifles I have seen from various brands that are labeled as having 556 chamber barrels when they guage at 223 and need to reamed.

They are fun, unfortunate the market is screwed up right now with a lot of artificial inflation.
Dave

[rukwikenuf]

the difference in lower parts is important too... a cheap CMMG kit will have a cheap CMMG trigger. a quality trigger is something that you'll NEVER regret (not to say that it has to be a Geissle or Timney, but a quality trigger vs. milspec)

bbls: any lining, and i mean ANY lining, will be uneven. the question is HOW uneven. when a bbl is machined from chromoly steel and then chromed/melonited/NiB/other wonder coating, it adds to the thickness of the ID on the bbl. therefore, the bbl's ID will have to be made too big to make up for the plating process, and hopefully the plating will fill it to perfection. a PRECISION bbl will not be plated. now, i realize you probably don't really care about 3" groups at 600 yards, but the likelihood of pulling that off with a 14.5" ChroMo "machine gun" bbl is slim. some companies do a better job than others with their plating, but in general, a non-plated bbl will outshoot a comparable bbl that IS plated

as for the receivers, that's cosmetic. some have full ambidextrous controls (KAC and POF come to mind, also the SIG M400), some have bigger magwells (Noveske GenII) and integral trigger guards (likely every milled lower and then the Noveske GenII forged unit)

i'll stick with stainless bbls for the moment, they clean up easily and can be machined to tighter tolerances than a bbl that's to be plated.

my $.o2

[Dave Timm]

Actually that is incorrect with melonite barrels. Melonite is a chemical surface treatment. Our blanks are drilled, bored, and rifling cut true to size, much like a stainless barrel. Then the barrels are qpq treated while remaining true to size. You are correct with chrome lining that the rifling bore is slightly larger to allow for the thickness of the chrome lining. Then defincienies, build ups etc can be found with chrome lining. This is one of the reasons I prefer melonite treated barrels or stainless barrels for me. For what it's worth we also list and guarantee a 1 MOA accuracy spec at 100 yards with all of our barrels. I don't know of many manufacturers that list that on their chrome lined barrels. Not trying to sell as I know my views can be seen as biased but just wanted to get the correct info out.

I agree with you 100% on lower parts kits etc. there is a difference in not only castings, but carbon level in steel and final machining and finish. There is a reason some lower parts kits cost more then others.
Thanks
Dave

[yuppiejr]

Melonite is not a plating/material additive treatment, it's a chemical bath of the steel that causes a chemical change to the surface layer of steel that imparts additional hardness and lubricity without adding material. Chromoly steel rifle barrels can be produced to the same dimensions as stainless (prior to the melonite/nitride process) for identical accuracy but better long term barrel life if they are produced to otherwise identical specifications. YMMV depending on what type of stainless (410/416/etc..) and, more importantly, how much you rapid fire to heat up your barrel where stainless has a tendency to retain heat (thus it's great for cookwear) and can experience chamber/throat erosion more quickly than chromoly steel with chrome lining or a nitride/melonite treatment. It is my understanding that HOW FAST a rifle is fired is far more important to the life of the barrel than how many shots total, and in the case of a semi-auto AR stainless can be less desirable for this reason if the user likes to mag dump.

I think all three are good barrel materials with different applications depending on the end-user, I've owned/recommended AR's with all 3 and the folks using them haven't reported any complaints.

As for what makes a good AR...

Does it go bang when it should and allow you to hit what you're aiming at in the worst conditions you'll experience while attempting to do so? Must be a good AR for you. The other stuff is, for the most part, insurance and manufacturing standards/certifications that can increase the odds (but not guarantee) and up the price to have the experience described in the first sentence of this paragraph. The amount of money people are willing to pay for this peace of mind varies wildly.