Stainless steel barrels: how long are they "combat accurate"?

[DreadPirateMoyer]

Hey there M4Cers,

I've been heavily considering a Wilson Combat, Larue, or Noveske AR-15 with SS barrel. I know that the above are generally sub-MOA accurate for approximately 5,000-10,000 rounds (depending on who you ask: the manufacturer or bench shooters :p), but my question for you guys is unrelated to that. I'm more concerned with the barrel's longevity as a measure of its ability to continue being combat accurate. From my perspective, that's 3 MOA with quality ammo, though I'd be lying if I said I actually had any experience to tell me if 3 MOA is truly adequate in a combat scenario or not.

So, M4C: how long do high-end SS barrels (and yeah, they're made of different materials) last in combat conditions/uses with combat accuracy being the goal? Since they start more accurate than carbon-steel barrels, do they have an equal "combat accuracy" lifetime?

Thanks everyone. :)

[RyanB]

Costa told RECOIL magazine that his rifle shot 2.5" at 15,000 rounds.

[a0cake]

See my post (and some other good ones) in this thread:

http://mail.m4carbine.net/showthread.php?t=96571

It's not exactly the same question you're asking, but there's a lot of overlap. The basic question was "would you use a SS barrel for a duty weapon?"

The response I gave in that thread was this:

Sure would, and do. I'm somewhat of an "accuracy nut," and give minor advantages in precision between platforms a lot more consideration than I think most people do. A 0.5 MOA difference in accuracy can make or break my relationship with a rifle.

Because of this, and also because of the fact that my particular profession requires very precise shooting sticks, I have moved almost exclusively to SS barrels for both work (incidental) and personal rifles (intentional).

For what it's worth, I wouldn't worry too much about the durability of a Stainless barrel for the vast majority of applications. Here's how I'll qualify that statement:

I've personally put somewhere around 12K rounds of MK262 through an issued MK12 Mod 1 both in training and overseas in the last few years. All rounds were shot suppressed and some were F/A as it was on an M16A1 lower. F/A fire is not really in the job description for a MK12 but given the capability I chose to become intimately familiar with operating the rifle in this way. The firing schedule over the course of those 12k rounds was varied. Sometimes I would only need to shoot 10 or 15 rounds in one engagement over the course of a few hours...on really bad days it would see 6 or 7 magazines in 10 minutes.

The barrel was new when I got it so I had a blank slate to work with, which is always a good feeling with an issued gun. Anyway, I established an accuracy baseline in the beginning and found it to be a solid 3/4 MOA gun with MK262. Fast-forward 20 months and 12 thousand rounds (I'm anal about logging round counts with my rifles). I have a ritual of going out to the range every two weeks when possible to confirm zero and make sure accuracy is where it needs to be. Even at the end of my time with that rifle it was still producing the same boringly accurate results after 12k rounds.

Corrosion wise, I had no issues. The rifle saw austere conditions, summer time humidity, rain, winter sleet and snow...but I always made sure it was oiled and clean. If you take care of a stainless barrel it will take care of you. Neglect it and it and you will have problems. Even relatively cut off from the supply chain in the Afghan mountains, myself and everybody else in the section with stainless barrels was able to keep them in A+ condition. Non-issue unless you plan on not being around a decent CLP for months at a time. That's not real life. While important for somebody's end of the world fantasy, not being able to get CLP on and in the barrel is not a real world consideration.

On the personally owned side of things (the following is taken from a previous post of mine but much of it applies here):

What I've noticed about my BCM SS410 barrel is that groups do in fact open up when the barrel gets extremely hot but POI does not shift. The groups just expand but stay centered. Even when the barrel gets to this point (extremely hot), my groups won't open up past 1.5 MOA...better than many chrome lined barrels when cool, and far better than most chrome lined barrels when hot. In the last few months I've put 5K rounds through my SS410 and have noticed no degradation in accuracy. It still prints 1/2 to 3/4 MOA 10 shot groups, only opening up beyond that when really really pushed heat wise.

------------------------------------------------------------------------

Now, after all that, here's what I think people need to look at when selecting a stainless vs chrome lined barrel.

- Are you in a position to be able to feed it exclusively match grade ammunition? There's no point in going stainless if you're shooting M855. The best barrel in the world won't make inaccurate ammunition shoot straight. If you can't afford / can't use match ammunition for whatever reason...go chrome.

- If the answer to above is YES, then you are either pretty well off financially or your unit or organization is in a place to provide it. In either of these cases, the monetary cost / practical difficulty of a replacement barrel will be absolutely trivial in comparison to the cost and availability of ammunition. In other words, if you can afford 10-15k rounds of match ammunition, you can afford a new barrel. If your unit / organization can get that much match ammunition, it can get you a new barrel. In either case, barrel life is a non issue.

- Corrosion problems and sudden catastrophic failures from high volumes of fire are in my experience not relevant or warranted fears. I'm not trying to tell war stories here but I've asked a lot out of stainless barrels in some engagements as large and frenzied as you can imagine in the valleys and mountains of eastern Afghanistan. I don't forsee many other stainless "duty" barrels being faced with 125 red bearded nutjobs advancing down the mountain toward them. Having been in such situations with a stainless barrel I have to question the veracity of anybody who claims that SS barrels are not durable enough for "combat." Gotta wonder what they're basing that off of. Rest assured that a good stainless barrel is more than durable enough for combat conditions. Deliberately doing 10 mag dumps in a row on the range for Youtube is another story. Also not real life.

So, my position is that if you can take an honest look at yourself and determine that A) you can shoot to the potential of a match type barrel and B) you can afford to feed it a high quality diet and C) You don't mind the extra weight from the SS and beefier contour and D) you will not neglect to maintain your equipment...that you in fact SHOULD choose a stainless barrel for the edge in accuracy.

If the answer to any of these or the above questions is NO...go chrome.

------------------------------------------------------------------------------------------------------------------------------------------------------------------

Here's me shooting the MK12 F/A so you know I'm not BS'ing you. You can see the smoke coming of the OPS INC 12th and the paint peeling away, even though the photo is a bit blurry. The gun was not babied but not abused either:

http://www.hunt101.com/data/500/mk121.jpg

[a0cake]

Costa told RECOIL magazine that his rifle shot 2.5" at 15,000 rounds.

While that number sounds legit, I haven't put stock in any numbers Costa has given after he claimed that the PredatOBR was printing consistent 1/2 MOA groups with standard M193 type ammunition. Sure dude.

[RyanB]

I wouldn't have posted it if it didn't sound true to me.

In fairness, there's a mod on Lightfighter that claimed to consistently shoot 1/4 minute groups with M855 and his M16. Beats Costas claims by a fair margin.

[a0cake]

I wouldn't have posted it if it didn't sound true to me.

In fairness, there's a mod on Lightfighter that claimed to consistently shoot 1/4 minute groups with M855 and his M16. Beats Costas claims by a fair margin.
I don't care if he's a Tier 0 operator in Echo Force. That's a load of shit. :suicide:

Nothing personal against you as you're just relaying the information. But seriously - LOL.

M855 is well known to be ~ 4 MOA ammo. Certain lots are even worse. I'll be generous and call it 4. That means that the guy is claiming consistent groups that are 1600% smaller than average.

Let's look at the scale of that error:

- If the average adult is 6 feet tall, this dude's adult is 4.5 inches tall.
- If the distance from California to New York is 2900 miles, this guy only has to drive 181 miles.
- He can fly from New York to London in 26 minutes.

I think that should do it. This one can be confidently placed in the "debunked" pile.

[vicious_cb]

While that number sounds legit, I haven't put stock in any numbers Costa has given after he claimed that the PredatOBR was printing consistent 1/2 MOA groups with standard M193 type ammunition. Sure dude.

Its possible...with cherry picked 2-shot groups :rolleyes:

[Dave L.]

I don't care if he's a Tier 0 operator in Echo Force. That's a load of shit. :suicide:


You will never start the next bestest shooting school with that attitude :p

[El Cid]

I've posted this before but... Last November I personally watched Pat McNamara shoot a sub MOA group with his LaRue rifle that had 18,000+ rounds through it.

[rjacobs]

I've posted this before but... Last November I personally watched Pat McNamara shoot a sub MOA group with his LaRue rifle that had 18,000+ rounds through it.

with match ammo? I would probably believe it. I think these guys above are talking about run of the mill M193 or M855 which aint all that accurate IMO, but I dont believe its intended to be either.

[JSantoro]

M855 is well known to be ~ 4 MOA ammo.

If only...! It's more like 6, these days. They've gotten two waivers for the accuracy spec, one for primers, IOT keep up with production at the height of festivities. As the spool-down happens....given M855A1, there's no reason for them to tighten it up again....unless we hear the popping noise of somebody's head being pulled from their ass, once they realize how many guns they're breaking with that overpressured go-green crap.

Unsurprisingly, I'm with a0: If one is prepared to buy a SS barrel, then buy the amount of good ammo and range time it takes to slug the thing, one is posessed of the money to replace said SS barrel, regardless of what round-count it takes to slug the thing. "How many...?" is kind of a moot question, in the face of all the other logistical ones that need be answered.....or is at least one that can by answered by saying "As many as it takes!"

Yeah, they're gonna wear somewhat faster, but it's no easy thing to pin a number to it.

If it's "I wants a sooper-dooper akkerate barrel derp derp!" when buying Wolf, Remington UMC, PMC and the like.....an SS barrel is lost on those poor brainless souls, but it IS a free-market economy. Fools are parted from their money every day.

If 3MOA is one's chosen spec, just say 3MOA. I'll be kind and assert that "combat accurate" is a meaningless phrase, on a par with nonsensical verbal diarrhea like "knockdown power." Accuracy/precision isn't based upon an event, otherwise we'd be able to define a "Debutante Cotillion-Accurate" weapon or an "Arbor Day-Accurate" weapon, and that's a world I don't want to live in.

[lifebreath]

... That means that the guy is claiming consistent groups that are 1600% smaller than average.

Let's look at the scale of that error:

- If the average adult is 6 feet tall, this dude's adult is 4.5 inches tall.
- If the distance from California to New York is 2900 miles, this guy only has to drive 181 miles.
- He can fly from New York to London in 26 minutes.


I usually think you're full of it yourself, but that's pretty damn funny!

[markm]

In fairness, there's a mod on Lightfighter that claimed to consistently shoot 1/4 minute groups with M855 and his M16. Beats Costas claims by a fair margin.

You can do this if you shoot 5 round groups and toss out 4 fliers.

[jwfuhrman]

After 3 years and 15,000 rounds of 55gr hand loads(M193 clone), and 69gr SMK hand loads, I have had 0 loss of accuracy in my 16in BCM SS410 middy that occupies my 3gun rifle.

[Norman]

Hey there M4Cers,

I've been heavily considering a Wilson Combat, Larue, or Noveske AR-15 with SS barrel. I know that the above are generally sub-MOA accurate for approximately 5,000-10,000 rounds (depending on who you ask: the manufacturer or bench shooters :p), but my question for you guys is unrelated to that. I'm more concerned with the barrel's longevity as a measure of its ability to continue being combat accurate. From my perspective, that's 3 MOA with quality ammo, though I'd be lying if I said I actually had any experience to tell me if 3 MOA is truly adequate in a combat scenario or not.

So, M4C: how long do high-end SS barrels (and yeah, they're made of different materials) last in combat conditions/uses with combat accuracy being the goal? Since they start more accurate than carbon-steel barrels, do they have an equal "combat accuracy" lifetime?

Thanks everyone. :)

Maybe not a direct answer to your question but here are my thoughts.
If you’re buying a barrel because it’s “sub moa accurate” wouldn’t you want to replace it before it got to the 3 moa point? If you can afford the ammo to wear out a barrel, you can afford to buy another one. Just my .02

[MarkG]

Hey there M4Cers,

I've been heavily considering a Wilson Combat, Larue, or Noveske AR-15 with SS barrel. I know that the above are generally sub-MOA accurate for approximately 5,000-10,000 rounds (depending on who you ask: the manufacturer or bench shooters :p), but my question for you guys is unrelated to that. I'm more concerned with the barrel's longevity as a measure of its ability to continue being combat accurate. From my perspective, that's 3 MOA with quality ammo, though I'd be lying if I said I actually had any experience to tell me if 3 MOA is truly adequate in a combat scenario or not.

So, M4C: how long do high-end SS barrels (and yeah, they're made of different materials) last in combat conditions/uses with combat accuracy being the goal? Since they start more accurate than carbon-steel barrels, do they have an equal "combat accuracy" lifetime?

Thanks everyone. :)

I think you meant to say chrome lined carbon steel. Given the same ammunition and firing schedule, a chrome lined 41V50 barrel should double the life expectancy of a stainless barrel when constrained to their respective envelopes of accuracy.

[Hazborgufen]

How does this relate to a low profile stainless barrel? Noveske has a 16" lightweight stainless barrel that weighs 29 ounces, as compared to their 16" recon barrel that weighs 35 ounces. Best I can tell is that the weight savings is really the only difference in construction between the two. I'm guessing that the lighter barrel will heat up and cool down faster, but are there any other differences? Are there any real advantages to the heavier barrel?

[JC0352]

It is threads like this that make this place.

One can grow up with firearms from a young age, even carry one into harm's way as a grunt, and still not know much of anything, without a resource such as this.

Thanks for the knowledge!

[RIDE]

I don't care if he's a Tier 0 operator in Echo Force. That's a load of shit. :suicide:

Nothing personal against you as you're just relaying the information. But seriously - LOL.

M855 is well known to be ~ 4 MOA ammo. Certain lots are even worse. I'll be generous and call it 4. That means that the guy is claiming consistent groups that are 1600% smaller than average.

Let's look at the scale of that error:

- If the average adult is 6 feet tall, this dude's adult is 4.5 inches tall.
- If the distance from California to New York is 2900 miles, this guy only has to drive 181 miles.
- He can fly from New York to London in 26 minutes.

I think that should do it. This one can be confidently placed in the "debunked" pile.

Could not have been said any better.

[C-grunt]

How does this relate to a low profile stainless barrel? Noveske has a 16" lightweight stainless barrel that weighs 29 ounces, as compared to their 16" recon barrel that weighs 35 ounces. Best I can tell is that the weight savings is really the only difference in construction between the two. I'm guessing that the lighter barrel will heat up and cool down faster, but are there any other differences? Are there any real advantages to the heavier barrel?

I called Noveske a while back and asked them about the light weight profile they had in the Hunter line. They said that its just as accurate but will heat up faster and lose accuracy faster during firing strings.

[sinister]

Once a stainless barrel has hit its end of useful life you'll start seeing accuracy suddenly drop off a cliff. Groups will start growing and shots will be off-call. Commercial chro-moly or chrome-lined GI chro-moly vanadium barrels lose their accuracy edge over a gentler decline slope.

A barrel dies at its throat and muzzle. Your best tool for checking is a borescope, but proof will be on-target performance.

If you're shooting real M855 or M193 I doubt you'll notice as that shit will group all over the side of a deuce-and-a-half, relatively speaking. GI MILSPEC acceptance of the gun-rifle combo is within 6 MOA, although real life has it around 1.5 - 2 MOA. If you never shoot past 100 yards you'll probably never notice.

Military armorers almost all use a throat erosion gage which does nothing except show you how big the throat is and how far your leades may be eroded. These measurements are all relative if you didn't gage the gun as-new before you started shooting.

A chrome-lined barrel seems to last longer, but borescoping and sectioning still show throats erode and chrome wears and chips on the highest points of rifling leades where bullet ogives initially contact rifling lands.

[Shabazz]

For a longer lasting SS barrel, get a Noveske polygon rifled barrel.

This is my personal opinion. I do not work there.

[DreadPirateMoyer]

Wow. This forum is an absolute treasure trove of information. Huge thanks to everyone who replied.

I think, with all of the knowledge I've gained here, I'll be sticking with carbon-steel (nitride or chromed) barrels, as I'm shooting for 3 MOA accuracy; it seems like, by the time a SS barrel reaches this point, it will already be rapidly decreasing in the precision department.

Babam!

[RyanB]

I don't care if he's a Tier 0 operator in Echo Force. That's a load of shit. :suicide:

Nothing personal against you as you're just relaying the information. But seriously - LOL.

M855 is well known to be ~ 4 MOA ammo. Certain lots are even worse. I'll be generous and call it 4. That means that the guy is claiming consistent groups that are 1600% smaller than average.

Let's look at the scale of that error:

- If the average adult is 6 feet tall, this dude's adult is 4.5 inches tall.
- If the distance from California to New York is 2900 miles, this guy only has to drive 181 miles.
- He can fly from New York to London in 26 minutes.

I think that should do it. This one can be confidently placed in the "debunked" pile.

Your meter needs recalibration. I was mocking him.

[a0cake]

Your meter needs recalibration. I was mocking him.

I know; I'm making fun of him with you. That's why I tried to say I understood you were just relaying and not endorsing it at all. Sorry if that was unclear.

[a0cake]

I usually think you're full of it yourself, but that's pretty damn funny!


Interesting. Not sure why that was necessary - wish you'd leave GD disagreements there. The technical posts I make that involve quantifiable information should stand on their own and be challenged on their own merits not because of disagreements about religion and politics.

[RyanB]

I know; I'm making fun of him with you. That's why I tried to say I understood you were just relaying and not endorsing it at all. Sorry if that was unclear.

No worries. I drove 600 miles across four states today, that's my excuse!

[markm]

What are you hens squaking about? :p

[1859sharps]

I've been heavily considering a Wilson Combat, Larue, or Noveske AR-15 with SS barrel. I know that the above are generally sub-MOA accurate for approximately 5,000-10,000 rounds (depending on who you ask: the manufacturer or bench shooters :p), but my question for you guys is unrelated to that. I'm more concerned with the barrel's longevity as a measure of its ability to continue being combat accurate. From my perspective, that's 3 MOA with quality ammo, though I'd be lying if I said I actually had any experience to tell me if 3 MOA is truly adequate in a combat scenario or not.

In reading up on high power matches and equipment a few years ago I can across some comments that seemed to indicate that the that the 5000 - 10000 "rule" came from the Military marksmanship units figuring out a "max" number of rounds on average a particular type of barrel could have put through it and not see any loss of accuracy. Then they would just automatically swap barrels and not worry about it. Basically the theory went they have figured they could shoot say 5000 rounds out of X type barrel using Y type ammo and could almost guarantee no lost of accuracy. then rather than get "caught by surprise" at the 5000 round point, automatically change out the barrel.

Assuming that is true, the military has the budget to do this, most of us don't.

The other source of the 50000 - 10000 round rule seems to be just assuming a 223 would burn out barrels as fast as 308 would. which turned out to not be the case.

I also found credible comments by long time competitors that indicated they could get 15,0000 plus rounds out an AR barrel if they took care of it. basically worked to not over heat it, used the minimum powder charge to achieve their goals etc.

Soooo, what does this mean to the OP. Basically unless you run a max powder load and continually try and fire off a 30 round mag as fast as you can each and every time you shoot your rifle, and unless you get a lemon of a barrel I would think you would get easily 15,000 rounds of life out of it.

At what distance were you wanting to maintain 3moa ?

[justin_247]

Thank you, a0cake, for your posts. I just learned a lot, and for that I am always appreciative.

[Suwannee Tim]

I wouldn't have posted it if it didn't sound true to me.

In fairness, there's a mod on Lightfighter that claimed to consistently shoot 1/4 minute groups with M855 and his M16. Beats Costas claims by a fair margin.

Imagine what he could do with a proper bench rest gun. I'll bet he could shoot 0.01 MOA. One hole groups at 1,000. I'd like to take some shootin lessons from this guy.

While you guys are in a BS calling mood, today I shot a five shot, 200 yard, offhand, six inch group, with a 458 Winchester magnum, CZ 550 American Safari Magnum, Leupold M8 4X scope.

[jwfuhrman]

Imagine what he could do with a proper bench rest gun. I'll bet he could shoot 0.01 MOA. One hole groups at 1,000. I'd like to take some shootin lessons from this guy.

While you guys are in a BS calling mood, today I shot a five shot, 200 yard, offhand, six inch group, with a 458 Winchester magnum, CZ 550 American Safari Magnum, Leupold M8 4X scope.

can u teech me too shootz?

[Anomic]

Imagine what he could do with a proper bench rest gun. I'll bet he could shoot 0.01 MOA. One hole groups at 1,000. I'd like to take some shootin lessons from this guy.

While you guys are in a BS calling mood, today I shot a five shot, 200 yard, offhand, six inch group, with a 458 Winchester magnum, CZ 550 American Safari Magnum, Leupold M8 4X scope.

Big bores can be suprisingly accurate. Id say that one is possible.

[Sgt_Gold]

So, M4C: how long do high-end SS barrels (and yeah, they're made of different materials) last in combat conditions/uses with combat accuracy being the goal? Since they start more accurate than carbon-steel barrels, do they have an equal "combat accuracy" lifetime?


My question is at what distance are you needing the sub MOA accuracy? A stainless barrel that is no longer shooting on call at 600 yards can still be hammering at 300 yards. Also, as others have pointed out you need match grade ammo to exploit the match grade barrel. M855 ain't gonna cut it.

[donwalk]

IMO..too many variables in play to accurately predict how long any barrel will perform accurately...

[a0cake]

Are you seriously seeing USGI M855 shooting around 1.5-2MOA?

If you don't mind my two cents, early lots of M855A1 were shooting very well and pretty close to the above accuracy spectrum. Speaking for myself only, I haven't seen the older M855 green tip do anything close, and even later lots of the A1 settled into mediocrity when I last used it in mid-2011, but was still better than green-tip.

[markm]

Are you seriously seeing USGI M855 shooting around 1.5-2MOA?


I've shot 2 MOA with IMI M855 and an A2 rifle.

Maybe I can talk Pappabear into running some Real M855 LC through his precision Bolt gun this weekend. And while we're fouling the barrel with nasty ball powder... we'll run XM855 to see if it's any sloppier.

[sinister]

I have, with real no-shit Lake City GI M855 out of M16A2s with brand-new barrels at 100. None of the "XM" or "PD" commercial or surplused Green Tip.

Further out Green Tip starts to make bigger and nastier groups, but will still hit an E-type at 300. not necessarily on-call, but it'll hit.

[Surf]

As far as SS goes, most of mine have been precision oriented and round counts or more importantly I did not pound rounds out of them so they are not near a lifespan issue. I will say that I do have some great Colt barrels that keep pace with some of my best SS barrels. Rare, but those barrels are out there.

My last build using a SS barrel is a Noveske 16" LW SS barrel that was put together in Jan 2012. This rifle is more of a 3 gun type of build and I am definitely heating that thing up and running it hard. I will note that I baselined the rifle for groups with a few different ammo types. Due to a huge emphasis on teaching, my own training or shooting schedule is not nearly where I would like it to be and I am not shooting this particular rifle nearly as much as I wished, but I should hit around 10K by the end of the year. My schedule is booked solid through the end of the year but If I get more time to play after the new year I hope to get at least 15K on it pretty quickly. I am shooting 100y groups at about every 2000 rounds. No noted differences so far with ~ 6K on the rifle. I understand that this is only a sample of one, but I figured I would track this to suit my own curiosity.

[Sierra276]

aO ... Nice Photo... Doing " The Walk "...

Looks like you need to clean up your playground... It's a mess...:D

[bobslife6826]

This is a very interesting topic to me.........

What our your opinions on say, buying a quality SS Noveske barrel and then sending it of to a company that can NiB-X the outside of the barrel, and more importantly the barrel extension. Then coat the bore with a Nitromet Salt Bath Nitrocarburizing (e.g., Melonite).

Supposedly this may be the best of both worlds, as you would have the accuracy of SS, with the longevity of chrome lining.

Look at this barrel as an example:
http://www.wmdguns.com/shop/cart.cfm?cmd=view.item&tcat=4&scat=2012&productid=144

How would the coating effect the internal dimension of the bore?

How would the accuracy be effected, as to an uncoated SS barrel?

Or would this just ruin an already great Noveske SS barrel?

What our your opinions..............Thanks

[MarkG]

This is a very interesting topic to me.........

What our your opinions on say, buying a quality SS Noveske barrel and then sending it of to a company that can NiB-X the outside of the barrel, and more importantly the barrel extension. Then coat the bore with a Nitromet Salt Bath Nitrocarburizing (e.g., Melonite).

Supposedly this may be the best of both worlds, as you would have the accuracy of SS, with the longevity of chrome lining.

Look at this barrel as an example:
http://www.wmdguns.com/shop/cart.cfm?cmd=view.item&tcat=4&scat=2012&productid=144

How would the coating effect the internal dimension of the bore?

How would the accuracy be effected, as to an uncoated SS barrel?

Or would this just ruin an already great Noveske SS barrel?

What our your opinions..............Thanks

I believe NiB-X and Nitromet are same thing. Nitrocarburizing is all or nothing process. I suppose you could plug the muzzle and breach to prevent the bore from being treated but who would want to? I doubt there is a way to treat just the bore and chamber.

[bobsolla]

This is a very interesting topic to me.........

What our your opinions on say, buying a quality SS Noveske barrel and then sending it of to a company that can NiB-X the outside of the barrel, and more importantly the barrel extension. Then coat the bore with a Nitromet Salt Bath Nitrocarburizing (e.g., Melonite).

Supposedly this may be the best of both worlds, as you would have the accuracy of SS, with the longevity of chrome lining.

Look at this barrel as an example:
http://www.wmdguns.com/shop/cart.cfm?cmd=view.item&tcat=4&scat=2012&productid=144

How would the coating effect the internal dimension of the bore?

How would the accuracy be effected, as to an uncoated SS barrel?

Or would this just ruin an already great Noveske SS barrel?

What our your opinions..............Thanks

i would like to know as well,since i have a 20"s.s. noveske medium varmint barrel on it`s way for an upper build.

[MistWolf]

Why bother coating stainless steel? Bare stainless steel is plenty tough and corrosion resistant. Bead blast it for a dull grey finish and put the money saved towards ammo, mags & training.

I forget which Wonder Coating it is, but one of them can actually reduce the corrosion resistance of stainless steel.

Stainless steel barrels are not more accurate than steel barrels. In fact, I recall when stainless steel was first being used for barrels, serious competition shooters avoided them like the plague because the bores were rough and other problems (real and imagined). Accuracy comes from how a barrel is made regardless of material or profile.

Chromoly bores erode smoothly and lose accuracy gradually. Stainless steel barrels do not. SS barrels end up looking like the cracked mud of a dried lake bed. Until the plates start breaking away, SS barrels hold consistent accuracy. Once the plates start breaking away, accuracy suffers very quickly. (Keep in mind, we're talking about competition accuracy. The barrel should still have some good life left in it for other purposes.)

If I recall, the military considers a barrel serviceable until bullets start keyholing. It takes quite a few rounds to wear a decent barrel to that point

[sinister]

For folks who don't know and are curious as to how long a barrel lasts, I think they're not shooting enough to be able to tell or know if it matters or not.

My guess is the overwhelming majority of AR owners in the United States will never wear out a single barrel, period.

[jbo723]

See my post (and some other good ones) in this thread:

http://mail.m4carbine.net/showthread.php?t=96571

It's not exactly the same question you're asking, but there's a lot of overlap. The basic question was "would you use a SS barrel for a duty weapon?"

The response I gave in that thread was this:

Sure would, and do. I'm somewhat of an "accuracy nut," and give minor advantages in precision between platforms a lot more consideration than I think most people do. A 0.5 MOA difference in accuracy can make or break my relationship with a rifle.

Because of this, and also because of the fact that my particular profession requires very precise shooting sticks, I have moved almost exclusively to SS barrels for both work (incidental) and personal rifles (intentional).

For what it's worth, I wouldn't worry too much about the durability of a Stainless barrel for the vast majority of applications. Here's how I'll qualify that statement:

I've personally put somewhere around 12K rounds of MK262 through an issued MK12 Mod 1 both in training and overseas in the last few years. All rounds were shot suppressed and some were F/A as it was on an M16A1 lower. F/A fire is not really in the job description for a MK12 but given the capability I chose to become intimately familiar with operating the rifle in this way. The firing schedule over the course of those 12k rounds was varied. Sometimes I would only need to shoot 10 or 15 rounds in one engagement over the course of a few hours...on really bad days it would see 6 or 7 magazines in 10 minutes.

The barrel was new when I got it so I had a blank slate to work with, which is always a good feeling with an issued gun. Anyway, I established an accuracy baseline in the beginning and found it to be a solid 3/4 MOA gun with MK262. Fast-forward 20 months and 12 thousand rounds (I'm anal about logging round counts with my rifles). I have a ritual of going out to the range every two weeks when possible to confirm zero and make sure accuracy is where it needs to be. Even at the end of my time with that rifle it was still producing the same boringly accurate results after 12k rounds.

Corrosion wise, I had no issues. The rifle saw austere conditions, summer time humidity, rain, winter sleet and snow...but I always made sure it was oiled and clean. If you take care of a stainless barrel it will take care of you. Neglect it and it and you will have problems. Even relatively cut off from the supply chain in the Afghan mountains, myself and everybody else in the section with stainless barrels was able to keep them in A+ condition. Non-issue unless you plan on not being around a decent CLP for months at a time. That's not real life. While important for somebody's end of the world fantasy, not being able to get CLP on and in the barrel is not a real world consideration.

On the personally owned side of things (the following is taken from a previous post of mine but much of it applies here):

What I've noticed about my BCM SS410 barrel is that groups do in fact open up when the barrel gets extremely hot but POI does not shift. The groups just expand but stay centered. Even when the barrel gets to this point (extremely hot), my groups won't open up past 1.5 MOA...better than many chrome lined barrels when cool, and far better than most chrome lined barrels when hot. In the last few months I've put 5K rounds through my SS410 and have noticed no degradation in accuracy. It still prints 1/2 to 3/4 MOA 10 shot groups, only opening up beyond that when really really pushed heat wise.

------------------------------------------------------------------------

Now, after all that, here's what I think people need to look at when selecting a stainless vs chrome lined barrel.

- Are you in a position to be able to feed it exclusively match grade ammunition? There's no point in going stainless if you're shooting M855. The best barrel in the world won't make inaccurate ammunition shoot straight. If you can't afford / can't use match ammunition for whatever reason...go chrome.

- If the answer to above is YES, then you are either pretty well off financially or your unit or organization is in a place to provide it. In either of these cases, the monetary cost / practical difficulty of a replacement barrel will be absolutely trivial in comparison to the cost and availability of ammunition. In other words, if you can afford 10-15k rounds of match ammunition, you can afford a new barrel. If your unit / organization can get that much match ammunition, it can get you a new barrel. In either case, barrel life is a non issue.

- Corrosion problems and sudden catastrophic failures from high volumes of fire are in my experience not relevant or warranted fears. I'm not trying to tell war stories here but I've asked a lot out of stainless barrels in some engagements as large and frenzied as you can imagine in the valleys and mountains of eastern Afghanistan. I don't forsee many other stainless "duty" barrels being faced with 125 red bearded nutjobs advancing down the mountain toward them. Having been in such situations with a stainless barrel I have to question the veracity of anybody who claims that SS barrels are not durable enough for "combat." Gotta wonder what they're basing that off of. Rest assured that a good stainless barrel is more than durable enough for combat conditions. Deliberately doing 10 mag dumps in a row on the range for Youtube is another story. Also not real life.

So, my position is that if you can take an honest look at yourself and determine that A) you can shoot to the potential of a match type barrel and B) you can afford to feed it a high quality diet and C) You don't mind the extra weight from the SS and beefier contour and D) you will not neglect to maintain your equipment...that you in fact SHOULD choose a stainless barrel for the edge in accuracy.

If the answer to any of these or the above questions is NO...go chrome.

------------------------------------------------------------------------------------------------------------------------------------------------------------------

Here's me shooting the MK12 F/A so you know I'm not BS'ing you. You can see the smoke coming of the OPS INC 12th and the paint peeling away, even though the photo is a bit blurry. The gun was not babied but not abused either:

http://www.hunt101.com/data/500/mk121.jpg

This post by itself should be tacked..Thanks for the info and your service aO..