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 Chrome moly barells vs chrome lined, what is the difference?
MikeE23666  [Team Member]
2/13/2012 4:51:09 AM EST
Are chrome moly barrels as good or better then chrome lined? Are they the same thing?

Are Milspec rifles chrome moly?

Thanks in advance,

Mike

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BRONZ  [Team Member]
2/13/2012 5:33:12 AM EST
Chromed lined is just that chromed. Chrome moly is inside bare steel barrel
lew  [Team Member]
2/13/2012 6:49:01 AM EST
Chrome-Moly is a steel alloy- usually 4140- with chrome and molybdenum, among other elements. Chrome-lined is just that.
Dredd308  [Team Member]
2/13/2012 8:59:28 AM EST
It is said that chrome lined barrels are easier to clean.

Mine is chrome lined so I can't say as I've never cleaned a non lined barrel.
dfariswheel  [Member]
2/13/2012 12:10:44 PM EST
The term Chrome Moly is often being used by lower end makers to give non-expert buyers the idea they're getting a chrome lined barrel.
As above, Chrome Moly is nothing more than a type of steel that's been used for gun barrels since the 1930's.

Chrome lined means the inside of the bore is coated with industrial hard chrome.
Chrome lined bores are easier to clean since fouling doesn't adhere to the "slippery" hard chrome.
They're also far more resistant to corrosion.
For these reasons, the military insists on chrome lined bores.
B44T  [Member]
2/13/2012 12:48:01 PM EST
Chromemoly is short for Chromium & Molybdenum, two metals alloyed with steel to improve its qualities fro certain purposes like gun barrels for example.

KRONIIK  [Member]
2/14/2012 2:08:30 PM EST
In terms of which is "better", the issue of accuracy should be addressed.
A chrome-lined barrel cannot be manufactured to the same tolerances that a non-lined barrel can.
In other words, the bore must be drilled oversize, and the grooves cut deeper than normal etc., to allow for the thickness of the plating, in order to achieve a desired final dimension. (Which may actually be a bit over or under spec, depending on how the plating process goes that day.)
Not saying that chrome-lined barrels can't be pretty accurate, some are pretty darn good.
But not to benchrest competition standards of pure accuracy.

If you doubt me, talk to a few national-level benchrest shooters and get back to me if they disagree.

I'd be surprised.
MFP_4073  [Member]
2/14/2012 2:25:57 PM EST
Originally Posted By KRONIIK:
In terms of which is "better", the issue of accuracy should be addressed.
A chrome-lined barrel cannot be manufactured to the same tolerances that a non-lined barrel can.
In other words, the bore must be drilled oversize, and the grooves cut deeper than normal etc., to allow for the thickness of the plating, in order to achieve a desired final dimension. (Which may actually be a bit over or under spec, depending on how the plating process goes that day.)
Not saying that chrome-lined barrels can't be pretty accurate, some are pretty darn good.
But not to benchrest competition standards of pure accuracy.

If you doubt me, talk to a few national-level benchrest shooters and get back to me if they disagree.

I'd be surprised.



This is how I always understood it.

Maximum corrosion resistance, you want chrome-lined.

Maximum accuracy potential, you do not want chrome-lined.

4073
va_gunz  [Member]
2/14/2012 4:53:41 PM EST
They are both Chromoly. One has a chrome lining.
Derek45  [Team Member]
2/14/2012 5:05:22 PM EST
Originally Posted By dfariswheel:
The term Chrome Moly is often being used by lower end makers to give non-expert buyers the idea they're getting a chrome lined barrel.
As above, Chrome Moly is nothing more than a type of steel that's been used for gun barrels since the 1930's.

Chrome lined means the inside of the bore is coated with industrial hard chrome.
Chrome lined bores are easier to clean since fouling doesn't adhere to the "slippery" hard chrome.
They're also far more resistant to corrosion.
For these reasons, the military insists on chrome lined bores.


+1000

Military barrels are chrome lined.

el-cheapo gunshow special used car salesman barrels are "chrome-moly"

BRONZ  [Team Member]
2/15/2012 11:27:10 AM EST
Just when u find a barrel u like cheap u find out its chrome moly.
KRONIIK  [Member]
2/15/2012 6:30:40 PM EST
Originally Posted By Derek45:
Originally Posted By dfariswheel:
The term Chrome Moly is often being used by lower end makers to give non-expert buyers the idea they're getting a chrome lined barrel.
As above, Chrome Moly is nothing more than a type of steel that's been used for gun barrels since the 1930's.

Chrome lined means the inside of the bore is coated with industrial hard chrome.
Chrome lined bores are easier to clean since fouling doesn't adhere to the "slippery" hard chrome.
They're also far more resistant to corrosion.
For these reasons, the military insists on chrome lined bores.


+1000

Military barrels are chrome lined.

el-cheapo gunshow special used car salesman barrels are "chrome-moly"



True. And so are some of the most accurate barrels ever made.
Obermeyer, Brux, Krieger, Pac-Nor, and many other custom barrelmakers have all made FINE match-grade barrels out of ChromeMolybdenum steel when for one reason or another stainless is deemed less suitable for a given application.

NOTHING wrong with a chromemoly barrel per se!
And you can chrome plate a chromemoly barrel, but it will probably be less accurate than it was before it was plated!
It will last longer though.
B44T  [Member]
2/16/2012 8:18:31 PM EST
The modern minimal etch hard chrome plating process is highly precise and and only replaces about two ten-thousandths of steel with hard chrome in the bore and four ten-thousandths in the chamber.
The barrel is dimensionally far more consistent than with any other method of plating.
sd9043ac  [Member]
2/16/2012 9:34:52 PM EST
Correct me if I am wrong. But are military barrels made with 4150 Chrome Moly Steel and Chrome Lined? I know Bushmaster makes there barrels that way. Don't know for sure about Colt.
KRONIIK  [Member]
2/17/2012 8:00:50 PM EST
Originally Posted By B44T:
The modern minimal etch hard chrome plating process is highly precise and and only replaces about two ten-thousandths of steel with hard chrome in the bore and four ten-thousandths in the chamber.
The barrel is dimensionally far more consistent than with any other method of plating.


Interesting info; I'll have to study up on that.
You have any personal or professional experience with said process, B44T?
HeavyMetal  [Team Member]
2/18/2012 7:01:24 AM EST
What I have heard is the chrome lining costs about a half moa in accuracy.

Unless you are shooting match grade ammo thru an SPR type rifle, accuracy is a moot issue. The end-user and ammo's influences will likely put this small difference well into the background noise.
ziarifleman  [Team Member]
2/18/2012 7:06:44 AM EST
Originally Posted By B44T:
The modern minimal etch hard chrome plating process is highly precise and and only replaces about two ten-thousandths of steel with hard chrome in the bore and four ten-thousandths in the chamber.
The barrel is dimensionally far more consistent than with any other method of plating.


If only there were some way to heat treat the barrels so they're harder than chrome and have no added dimension.

Golly, that'd sure be something.
HeavyMetal  [Team Member]
2/18/2012 7:16:23 AM EST
Originally Posted By ziarifleman:
Originally Posted By B44T:
The modern minimal etch hard chrome plating process is highly precise and and only replaces about two ten-thousandths of steel with hard chrome in the bore and four ten-thousandths in the chamber.
The barrel is dimensionally far more consistent than with any other method of plating.


If only there were some way to heat treat the barrels so they're harder than chrome and have no added dimension.

Golly, that'd sure be something.


You mean like a different process? Something that introduces something like nitrogen into the steel?.....hmmmm......sounds like having your cake and eating it too. I CALL WITCHCRAFT!!!!
ziarifleman  [Team Member]
2/18/2012 7:23:12 AM EST
Originally Posted By HeavyMetal:
Originally Posted By ziarifleman:
Originally Posted By B44T:
The modern minimal etch hard chrome plating process is highly precise and and only replaces about two ten-thousandths of steel with hard chrome in the bore and four ten-thousandths in the chamber.
The barrel is dimensionally far more consistent than with any other method of plating.


If only there were some way to heat treat the barrels so they're harder than chrome and have no added dimension.

Golly, that'd sure be something.


You mean like a different process? Something that introduces something like nitrogen into the steel?.....hmmmm......sounds like having your cake and eating it too. I CALL WITCHCRAFT!!!!


Burn them!!
Joe-A275  [Member]
2/18/2012 1:18:07 PM EST
To add, Chrome lined also adds reliability, especially in the AR15/M16 because of the type of Chamber/ Bolt.

My match rifles were all stainless steel, or chrome moly, the last one obermyer. It shot 1/2 MOA out of an AR10.
Which is incredible for a semi-auto. It also locked up about a 1/3 of the time in sniper matches in the field.
B44T  [Member]
2/21/2012 9:42:43 AM EST
Originally Posted By ziarifleman:
Originally Posted By B44T:
The modern minimal etch hard chrome plating process is highly precise and and only replaces about two ten-thousandths of steel with hard chrome in the bore and four ten-thousandths in the chamber.
The barrel is dimensionally far more consistent than with any other method of plating.


If only there were some way to heat treat the barrels so they're harder than chrome and have no added dimension.

Golly, that'd sure be something.



Minimal etch chroming doesn't add anything appreciable to the dimensions.

FWIW I believe conversion treatments like Melonite, for one example, seem to be gaining acceptance and could quite possibly surpass chrome as the lining of choice when economy of scale is achieved.
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