View Full Version : Chromed or 'lined' AR barrels - or not

November 11, 2012, 08:03 PM
Last week, the forum offered some good advice on the purchase of a 5.56 Lower for a provisional or future build.

The Smith & Wesson AR15 Sport I previously purchased has a proprietary Melonite lining/coating instead of a chrome liner.

So, on a purchased barrel, what are benefits or a chrome coating? Is it a wear issue, since chrome is harder, or is it resistance to corrosion from rust or powder/primer components? It's not my intent to shoot rounds with corrosive components if I can avoid it.

What advice?

November 11, 2012, 08:09 PM
The melonite is better. The coating is more uniform which means more accuracy. Both extend barrel life.

Not saying chrome can't be accurate, it can be. It's just more difficult to get it right as a mfg.

November 11, 2012, 08:14 PM
Melonite is a form of Nitrocarburizing. It will not be as thick as a chrome lining is since it is on the molecular level instead of a lining.


From what I read you better finish machining or drilling on a part before the treatment because the process hardens a part significantly.

I have owned a AR15 without the chrome lining and never had any problems.

November 11, 2012, 09:28 PM
So, can you buy a Melonite coated barrel? Or, just Chrome-lined, or bare?

November 11, 2012, 09:34 PM
A proper Melonited barrel> Chrome > plain. If you're just plinking, any would be fine.

November 11, 2012, 11:47 PM
Is stainless steel equivalent to some of the aforementioned materials insofar as accuracy and/or durability are concerned?

Metal god
November 12, 2012, 03:58 AM
I think you need to ask your self this question first . How many rounds do you think you will put down range in the life of the gun . This year alone I've shot 1,500+ rounds of 223/5.56 through 3 ARs . At the rate of 500 rounds a year any barrel will last many years . If you plan on only having 1 AR and shoot as much as I do . I would get a chrome lined barrel . When ever I buy a gun , I plan on keeping it for the life of me then handing it down to my son . I know it's stupid but I don't want him saying , hey I got all my dads guns but there all garbage cus he shot them into the ground . A chrome lined barrel should be good for 25,000+ rounds .A untreated chrome alloy vanadium barrel will shoot 10,000+ rounds . The melonite coated barrels expected life I do not know.

I would consider how many rounds you plan to put through the gun in it's/your life as well as what you plan to use it for .

If you plan on the gun being your HD/plinking gun and you plan to shoot the heck out of it . I recommend a lined/coated bore . If you plan to shoot competition and for accuracy you would not want it chrome lined and most likely stainless chambered in 223 wylde .

Hope this helps , if not never mind :D

November 12, 2012, 07:50 AM
What Metal god said.

Barrel accuracy is more about the quality of machining and barrel profile than any coating done to it.

99% of shooters do not come close to out shooting the barrel they have.

November 12, 2012, 08:45 AM
Always go with chrome lining on military style rifles. Round count may be relevant, but not the only thing to consider. If you ever have to actually use your AR for an extended period of time with cheap cruddy ammo, of course you would want a chromed barrel & bore. They don't chrome line AK's (or AR barrels) because it enhances their beauty.

November 12, 2012, 11:21 AM
I appreciate the last three posts.

My intent is likely in the 1k-2k round count per year. But, since I recently bought an M&P Sport, I'd be spreading that over two guns. Time and budget sadly don't allow more.... And then there is pistol practice, and reloading 30-06 and 30-30, etc, etc!

So, all I really wanted to do is to not short-change myself on barrel selection for a one-time purchase. Like MetalGod said, I want to hand all weapons down to my son and daughters if they want, and not leave them useless weapons.

Stainless sounds good to me, chrome moly vanadium barrel will likely suffice if the cost savings justifies it.

Sweet Shooter
November 12, 2012, 11:52 AM
I wouldn't be concerned about round count. It all comes down to heat and how well you look after the barrel. Don't burn it up with rapid fire or over clean it and it will outlast you. If you want "air" your testosterone (which is entirely your prerogative) then buy chromed. Experienced riflemen have ways to tell how a gun has been treated/cared for.

Think of it like a car. I'd rather buy a used car with 60k careful miles on it,—than the same model with 10k reckless miles and a few jumps thrown in for good measure—at the same price point.


November 12, 2012, 12:41 PM
Makes sense. I will not be shooting larger annual round counts, nor will I be emptying mags quickly. In fact, I bought 20 rd mags for my Sport to lessen the temptation a bit. And, at $0.35 - $0.40 per trigger pull, I'll be firing for accuracy and effect - not to lay down cover in my neighborhood (I hope!).

Any AR I have or will buy will be HD first, range therapy second, and small game hunting last.

Sweet Shooter
November 12, 2012, 01:20 PM
Roger that smokiniron. I bought a 5 round Bushmaster mag for the range. I love it's construction quality and it encourages me to get up away from the bench after every group. A scope may increase fire rate at the range as it's easier to get on target.

With irons my shots at 100 yards at the range take forever, as I'm never truly happy with my sight picture. I currently have a scope on it and I have to say it is very pleasing to get into ~one-inch groups. I have the A2 handle in my shooting bag. The A2 handle sight never appears to go out of zero when I remove/replace it.

November 12, 2012, 02:30 PM
I bought a 5 round Bushmaster mag

Good idea... I was looking at 10 rd mags for the same reason, but I think the 5-rd will make me think about the shots more as with my Savage and Marlin rifles. Crossroads of the West gun show this weekend in Salt Lake City! I'm looking for bulk range ammo and maybe a few 5 or 10 rd mags.

Sweet Shooter
November 12, 2012, 02:58 PM
Yes the show this weekend will be packed out I reckon. Ammo deals will disappear before 10:00 a.m. so I'm going to get there early. I'm looking for some too.

On that note, have you tried the Fiocchi 55 gr PSP yet? Gallenson's have a 5h1t load of it for 9 bucks and change for 20. I have stock-piled them. In all my guns they have shot around MOA for 10 rounds. In my SIG they shoot groups half the size of the groups PMC Bronze shoots.


chris in va
November 12, 2012, 03:04 PM
Since uou already reload, why not 223. Cuts the round cost in half, especially using surplus plinker bullets.

November 12, 2012, 03:06 PM
I'll check them. I work 4 blocks away from Gallensons, and drop by there a few times a month. Good call. I bought some Federal white box 5.56 M193 for $7.99 at Sportsman's Warehouse Sat night. I hear the 5.56/M198 is good for the first 100 rds to break in a new gun.

November 12, 2012, 03:07 PM
I haven't studied the economics of reloading .223. If it's close to 50%, that makes sense.

November 12, 2012, 07:57 PM
Here's more on hard chrome lined, stainless, and standard carbon barrels.

Standard carbon steel unlined barrels:
High quality barrels MAY BE slightly more accurate then hard chrome lined. This is not always the case and the difference is slight.
They're the cheapest barrels.
May benefit from a break in procedure.

They rust and corrode if not cared for.
They're the hardest barrels to get clean.
They don't last as long as the others.
Don't get taken by people advertising "Chrome Moly" barrels. Chrome moly is nothing more then ordinary carbon steel used in barrels since the 1930's.
Some sellers leave the impression the bores are lined with chrome by using the "chrome moly" term.

Stainless steel:
Very accurate.
Last longer then plain steel, but not as long as chrome lined.
Easier to clean.
Much less likely to rust or corrode.
For these reasons, virtually all Match rifles use stainless barrels.
Break in is much faster then carbon steel.

More expensive.
Bright finish unless coated or treated to darken it.

Chrome lined:
The most durable. This is the major reason the military will buy only chrome lined barrels.
Very easy to clean. Fouling won't adhere to the "slick" chrome as it does to carbon. Another reason the military buys it.
Highly resistant to rust or corrosion. The second major reason the military only buys chrome lined.
Requires no break in, and in fact, no break in is possible.
Tolerates high heat from rapid fire much better then stainless or plain carbon steel.

Often not quite as accurate as carbon or stainless. This is only an issue in accuracy Match type barrels where you're trying to get the last bit of accuracy out of the rifle.
In an ordinary rifle the average owner will not be able to detect any difference.
Costs more than carbon.

Bottom line: In a non-Match rifle like a standard AR, given the lifetime of the rifle versus the extra cost for hard chrome, it's sort of silly not to buy hard chrome.
The advantages far out-weight the extra cost.

November 12, 2012, 08:14 PM
I hear the 5.56/M198 is good for the first 100 rds to break in a new gun.
Curious on that. Seems just about anything that squirts a common projectile out the noisey end reliably would work for general rifle break-in. (NO- I'm not about to touch the barrel break-in thing again.:eek:) I bought a R-Guns upper some months back, put it on a new Doublestar(?) lower. I ran regular 55gr brass PPU ammo through it. After 40 rounds- it had no sluggishness or short strokes or anything else I might have found objectionable.

November 12, 2012, 10:05 PM
I heard that the chamber and bolt carrier benefitted from 100 rds of higher pressure ammo. No personal experience, though...

November 12, 2012, 10:07 PM
Excellent breakdown. Thank you. Your comments as with those of others have been extremely helpful and educational in learning about my new AR Sport, as well as future builds.

November 13, 2012, 12:31 AM
The primary reason the military went to chrome lining is not to save a GI from having to clean his weapon more often so it wouldn't rust or corrode.. The military weapons were full auto and shooting it that way could wear out a barrel in less time. Chrome lining would extend the barrel life of a military full auto weapon.

If you are a recreational AR-15 shooter who takes good care of his rifle you wouldn't notice any difference for years.

November 13, 2012, 07:45 AM
If I were putting together a rifle for target shooting or hunting I would not get a chrome lined barrel. But for range plinkng, all around use, or SD use I'd go chrome lined.

I realise I will most likely never actually use the gun for the purpose it was designed. But in the unlikely event it ever has to be used for that purpose, then I want it set up to give me any availible advantage, no matter how small.

November 13, 2012, 08:34 AM
If I were putting together a rifle for target shooting or hunting I would not get a chrome lined barrel.

If I could have a chrome lined barrel on every rifle, carbine and pistol I own, I would. Even my Savage 30-06, which I sometimes hunt with in poor weather, even snow. I'm constantly thinking about how the bore "might" be getting a little rusty.

Yes, I said pistol. I have a Steyr GB which has a chrome barrel and it is extremely accurate. Some folks like stainless - personally,I don't think it is as good as carbon steel with quality hardchrome. The carbon steel is over all harder than stainless, and the hard chrome makes it even that much harder. There's only one reason barrels aren't hard chromed - cost.

Sweet Shooter
November 13, 2012, 12:37 PM
@ Skans...

I agree. I'm not seeing a loss of accuracy, and in fact have been surprised seeing improvements.

A well made barrel is a well made barrel. Of course there's little hope for a dogs leg of a barrel that has subsequently been preserved in that state by chrome lining.

November 13, 2012, 12:38 PM
There are advantages to the chrome lined barrel. True. I wonder though, why does the .mil obtain "nitrided" or "melonite" M2 50 cal barrels then? From what I have read elsewhere that the melonite process yields a more wear resistant barrel than chrome.

I do not know whether it is similarly resistant to rust and corrosion, however.

November 13, 2012, 02:49 PM
Because chrome lining barrels involves toxic substances and EPA restrictions makes this process prohibitive, unless you are doing very large orders.

In fact the availability of chrome lined barrels is one of the major advantages to owing an AR, or even an AK. Now, if they would only make AR receivers in steel and gas pistons for .308, they'd almost be as good as a FAL.:D

November 13, 2012, 09:45 PM
Melonite trumps chrome for durability and corrosion resistance. I am surprised by claims of accuracy. Nitrided guns are noticeably textured when compared to blued, chrome, stainless. I can't imagine that texture led to a decrease in accuracy. I have nothing scientific backing that belief though.

Metal god
November 13, 2012, 10:13 PM
Melonite trumps chrome for durability and corrosion resistance.

Is this a general statement as to coating metals as a hole ? Or are you being spesific to chrome lining the bore , chamber , BCG ,and gas key . Like I said in a post earlier I do not know much about the process or how it compares .

November 13, 2012, 10:39 PM
If you have a little time, do some research on the net....you'll find info about it.

Metal god
November 13, 2012, 11:35 PM
Did a little research and I do mean a little . This is what I found so far .

The MELONITE and QPQ process increases fatigue strength about 100% on notched components made from unalloyed steel parts and about 30-80% on parts made of alloyed steels.( like a barrel ) The hardness is maintained up to about 930�F and extends the surface life of steel tools and components exposed to heat.

This study shows how hot the external temp of a M4 barrel can get ( page 24 ). Well over 1,000 degrees with very high rates of fire and teeters right around the 900 degrees mark at moderately high fire rates . Im sure the actual bore gets much hotter then the 930 degrees the melonite is designed to withstand .What does this mean to 99.9 % of us ? Most likely nothing .

Now for chrome lining I'll be back

November 16, 2012, 02:06 AM
Nitriding is an incredible firearm finish. I am a little bit crazy about finishes. IMO nitriding is way beyond anything else out there on every measure of utility. It is used heavily in Europe. To get a gun in the US with it you have to look hard or buy a European gun. I don't think it is even that expensive to do.

It is the ugliest finish though. Look at a Glock slide after it is holstered just a few times. Where it rubs the color changes. Drives some people crazy.

November 16, 2012, 08:08 AM
It is the ugliest finish though. Look at a Glock slide after it is holstered just a few times.

You think that makes a Glock ugly!!!:D:D:D