A few questions about chrome?

[mastiffhound]

Manufacturers have been putting out tons of new firearms because of the Great Gun Grab. Many have started (before the GGG) making specialized ARs for 3 Gun competition or what they call accurized AR models with no chrome lined chambers and bores. Most of their advertisements portray them as ultra reliable fighting rifles. Almost all companies have ARs like this for example Noveske, fine rifles I lust after daily.

I understand the extra accuracy because of tighter tolerances, it's never a bad thing. I've been led to believe most of my life that chrome lining was a big deal for reliability and longevity though? I was watching a 3 Gun match on one of the hunting channels and seen a guy shooting an AR with what looked like a stainless barrel have a few stuck cases. A number of things could have caused it but I started thinking and wondering why. I did hit the orange button but it mostly came up with guys defending melonite over chrome.

Am I missing something, so far as has chrome lining fallen out of favor? Just for the record I'm not into melonite as a substitute for chrome lining either. I'm not knocking anybody, I'm just looking for some helpful insight. As usual, thanks for the help gentlemen!

[Badger89]

I'm sure a few more experienced members will chime in with a better reply, and may even correct mine, but my understanding is that the original AR15 design did not call for a chrome lined bore and chamber, and was added after the fact by military requirement. I have heard that some of the malfunctions experience with the early M16s where due to the bore and chamber beginning to rust in humid environments (Vietnam). You could say that that was caused by improper care or by inadequate design, but regardless chrome lining greatly helped the situation. While it's not as corrosion resistant as melonite treatment, its a huge improvement over bare 4150 CMV. I have personally had 416 stainless steel barrels rust, but it was only light surface rust on the outside, not inside the bore (or not that I could tell at least) and it was easily removed with a bit of steel wool. This has only happened to me a couple times and only after I decided to case the rifle without cleaning it after it had been in a damp environment. That said, I also had a non-chrome lined DPMS 4140 CMV barrel before my enlightenment that I had repeatedly cased without cleaning, and I never noticed the bore develop any rust either.

The greater advantage off chrome lining is the increased hardness over bare chrome-moly or stainless steels which gives the barrel an increased resistance to wear. If you're looking for accuracy, avoid chrome lining. If you plan to do a lot of shooting with the rifle and need the barrel to withstand a heavier firing schedule, go with a chrome lined barrel if you can sacrifice a little accuracy, or look into melonite treatment.

[chuckman]

I understand (and appreciate) the reasoning for chrome re: rust-prevention and longevity; what I have a challenge with is understanding that the lack of chrome improves accuracy THAT much for 99% of shooters (competition or non-comp shooters).

[sewvacman]

Someone correct me if I'm wrong, but I believe it's because it's easy to unevenly apply the chrome lining that leads to the effect on accuracy. That's why chrome-moly, stainless and CHF barrels are a bit more accurate than chrome lined.
I think

[Skyyr]

I understand (and appreciate) the reasoning for chrome re: rust-prevention and longevity; what I have a challenge with is understanding that the lack of chrome improves accuracy THAT much for 99% of shooters (competition or non-comp shooters).


Someone correct me if I'm wrong, but I believe it's because it's easy to unevenly apply the chrome lining that leads to the effect on accuracy. That's why chrome-moly, stainless and CHF barrels are a bit more accurate than chrome lined.
I think

This is correct. The chrome-lining is applied after the barrels are rifled. Because of this, there's much more of a margin of variance in the barrel that results in unpredictability in accuracy. That is to say, it's not that chrome makes it inaccurate as it adds an extra variable that usually has a negative effect on accuracy.

Also, as chrome barrels wear, small cracks can develop that allow moisture under the chrome lining. This allows rust to set in, which eventually allows the chrome to separate from the barrel. This can also greatly impact accuracy. Because this happens suddenly and without warning, chrome-lined barrels are usually avoided by competition shooters and military marksmen in a precision role (since the last thing they want is an unpredictable change in accuracy).

Chrome lining functionally doubles the life of most barrels at the cost of accuracy. For your average combat troop, their rifles are only required to be accurate within 3MOA. Since the variance of chrome lining is usually in line with that, it's usually seen as an acceptable trade-off.

Some manufacturers, like BCM and Noveske have a chrome-lining process that allows the barrels to be chrome-lined almost as evenly as their unlined barrels. These are more accurate than traditional chrome-lined barrels (usually holding .75 - 1 MOA in most reports), but they still have a slight loss of accuracy due to the chrome lining. They also are potentially susceptible to the same chrome separation if rust gets under the lining.

[tommyrott]

I'm sure a few more experienced members will chime in with a better reply, and may even correct mine, but my understanding is that the original AR15 design did not call for a chrome lined bore and chamber, and was added after the fact by military requirement. I have heard that some of the malfunctions experience with the early M16s where due to the bore and chamber beginning to rust in humid environments (Vietnam). You could say that that was caused by improper care or by inadequate design, but regardless chrome lining greatly helped the situation. While it's not as corrosion resistant as melonite treatment, its a huge improvement over bare 4150 CMV. I have personally had 416 stainless steel barrels rust, but it was only light surface rust on the outside, not inside the bore (or not that I could tell at least) and it was easily removed with a bit of steel wool. This has only happened to me a couple times and only after I decided to case the rifle without cleaning it after it had been in a damp environment. That said, I also had a non-chrome lined DPMS 4140 CMV barrel before my enlightenment that I had repeatedly cased without cleaning, and I never noticed the bore develop any rust either.

The greater advantage off chrome lining is the increased hardness over bare chrome-moly or stainless steels which gives the barrel an increased resistance to wear. If you're looking for accuracy, avoid chrome lining. If you plan to do a lot of shooting with the rifle and need the barrel to withstand a heavier firing schedule, go with a chrome lined barrel if you can sacrifice a little accuracy, or look into melonite treatment.

actually stoners original design specs called for chromed chamber and bores, the wonder kids(mcnamara etc) decided to exclude it to speed up production for the war, also big green in its infinate wisdom switch powder specs(ball to stick) and also excluded cleaning kits because they were convinced somehow it was a self cleaning rifle? so after a few grunts got butchered and they're parents climbed up a number of politicians asses over piss poor equitment they started chromelineing bores and chambers and started issuing cleaning kits and including cleaning in training(more or less history channel)

[Badger89]

actually stoners original design specs called for chromed chamber and bores, the wonder kids(mcnamara etc) decided to exclude it to speed up production for the war, also big green in its infinate wisdom switch powder specs(ball to stick) and also excluded cleaning kits because they were convinced somehow it was a self cleaning rifle? so after a few grunts got butchered and they're parents climbed up a number of politicians asses over piss poor equitment they started chromelineing bores and chambers and started issuing cleaning kits and including cleaning in training(more or less history channel)
Thanks for the clarification.

[KiloSierra]

I understand (and appreciate) the reasoning for chrome re: rust-prevention and longevity; what I have a challenge with is understanding that the lack of chrome improves accuracy THAT much for 99% of shooters (competition or non-comp shooters).

Most of the top competitors are looking for any edge they can get even if they know it's only worth a point or two or a few fractions of a second at the most. A lot of lesser competitors look at what the top ones use to try and get they're scores up and a lot of people getting into stuff just figure if this guy's winning and using this, it must be good gear and what they need.

[Nka727]

If SHTF, 3 gun matches won't be taking place :lol:

[chungdae]

I know most people prefer a chrome lined barrel to a non chrome lined.

[Stickman]

.... making specialized ARs for 3 Gun competition or what they call accurized AR models with no chrome lined chambers and bores. ..... for example Noveske, fine rifles I lust after daily.


Which Noveske rifle or carbine are you referring to? I hope you aren't confusing SS barrels with regular unlined steel barrels.

[mastiffhound]

I've been looking at the 16" Recon, saving up at the moment. I just wasn't sure what kind of reliability and longevity I would get when say compared to a Colt or FN chrome lined barrel. If it is much lower then I was thinking of going with a Noveske 16" Light Recce Lo-Pro that is chrome lined. I'm not confusing the SS barrels with regular unlined steel barrels. Although some companies like DPMS have offerings like that, I couldn't imagine who would buy them?

I've just noticed that everyone is now advertising SS barreled AR's, while little or no advertising is done on their mil chrome lined AR's. That's why I asked if something had changed. After taking an honest look at my skill level I'm not sure if a SS barrel would help my groups all that much. It couldn't hurt though. Are SS barrels getting the same reliability and round counts as quality chrome lined barrels?

[Chorizo]

If SHTF, 3 gun matches won't be taking place :lol:

Sure they will, it is just that the targets will shoot back, the winner's prize will be that you are alive and the losers....well you get it.

Chrome was the solution to corrosive ammo that was commonly available in many third world countries and a solution for infrequently bore cleaning. It also provided around a 30% greater barrel life. Accuracy suffered for all the reasons previous posters stated above.

As with all things AR, your barrel selection should be based on your desired "mission profile". If you are happy with 2 MOA (not saying that good chrome barrels don't shoot better), want a longer barrel life, increased ease of cleaning, and increased reliability in extraction/chambering then a chromed barrel may be for you.

Improvements in barrel metallurgy have given us longer life barrels that are not chrome and because of the ability to maintain tighter tolerances without chroming are more accurate. Most (there are some exceptions ) match barrels and SPR barrels are not chromed lined.

[ejskle]

One thing to keep in mind: I believe that Noveske chrome-lined barrels have double-thickness chrome, which should improve longevity even more (it's the chrome spec for a much heavier gun).

I'm not sure who else does that.

[MegademiC]

A good barrel is a good barrel. A noveske ss bbl will usually be more reliable that an incorrectly made cl barrel. A good cl barrel will be more accurate that a crap as barrel.

If you need max accuracy, get ss. Outside of pro comps and hunting, I would get a cl. a good cl will produce 1-1.25 Moa groups with the right ammo.