AR Barrels

[Idagonian]

This is probably a newbie question. Is it a "given" that 5.56 AR barrels are going to be chrome lined? For example, I'm looking at a complete upper from Hardened Arms which lists the barrel specs as:

• 4150CMV Nitrogren Stress Relieved Barrel Steel
• Black Melonite/QPQ Finish
• Chambered in 5.56 NATO (will also fire .223 ammo)
• 6-Groove, 1/7 twist button rifled barrel
• 10.5" Socom Profile barrel with M4 Extension

I don't see something that refers to the inner lining of the barrel. Am I missing something?

Complete listing:
10.5" 5.56 10" HD Quad Rail Upper"%205.56%2010"%20HD%20Quad%20Rail%20Upper

Thanks!

Read More

 

[HB of CJ]

Unless specified probably not. Also ask for the specific type of chamber they are running.

 

[Salty_Socks]

If the barrel says that it is made of chrome molly steel, it will have a chrome lining. If it isnt, it will not have a chrome lining.

Seeing as how your barrel has the "CMV", which stands for,"chrome molly vanadium", on the barrel description, I think its safe to say that that specific barrel will have a chrome lining.

This is just what ive read though. So if I were you, I would try to google around and see if you could find a more definitive answer.

 

[HB of CJ]

Ah ... Respectfully. No. If the barrel is chrome lined it will say so. Stating the specific type of steel used is not stating that the bore and chamber are chromed.

Easy to visibly tell if a barrel has chrome lining. Pull the flash hider and look at the crown. The chrome will flash over the bore into the Crown area. Bright sliver or gray.

Also look at the barrel extension. Same thing. You will see flash over around the junction of the chamber and extension lug area. Finally a easy test that might still work.

Take apart a number 4 buckshot shell and tap the pellet through the bore then mike the swagged lead buckshot. It might read just a little bit tight which is good.

 

[titsonritz]

That barrel is not chrome lined. It is Melonite/QPQ.

 

[titsonritz]

Take apart a number 4 buckshot shell and tap the pellet through the bore then mike the swagged lead buckshot. It might read just a little bit tight which is good.

So why are we destroying shotgun ammunition and shoving foreign objects down our barrels?

 

[Salty_Socks]

Error

 

[HB of CJ]

Swagging/slugging interesting barrels with various sizes of buckshot is an old way of cheaply and quickly determining the condition of a barrel. Specifically remaining bore diameter which reflects remaining rifling. If you do not have a set of barrel diameter and barrel straightness gauges a cheap single round of buckshot can provide many pellets for determining bore diameter.

Casting a chamber and bore is the best way but lots of time the special casting alloy is not available. Enter the pure soft lead buckshot. It is tapped started like a muzzle loading black powder rifle then the buckshot is pushed through down the bore out the other end using an appropriate cleaning rod. Sometimes chrome lining slightly reduces the bore diameter. Just passing it forward.

 

[titsonritz]

Also, Id recommend going with something with a higher twist rate like a 1:8. Itll give you better performance out of higher weight bullets compared to a 1:7

You have that backwards

 

[Stomper]

Also, Id recommend going with something with a higher twist rate like a 1:8. Itll give you better performance out of higher weight bullets compared to a 1:7

LOL.... 1 twist in 8" is a slower (also lower) twist rate than 1 twist in 7".....


A 1:8 - 1:9 twist rate is a good compromise for 55gr and 64/5gr bullets, a 1:7 twist is good for 64gr and heavier bullets.

 

[Idagonian]

Thanks all!

 

[titsonritz]

Swagging/slugging interesting barrels with various sizes of buckshot is an old way of cheaply and quickly determining the condition of a barrel. Specifically remaining bore diameter which reflects remaining rifling. If you do not have a set of barrel diameter and barrel straightness gauges a cheap single round of buckshot can provide many pellets for determining bore diameter.

Casting a chamber and bore is the best way but lots of time the special casting alloy is not available. Enter the pure soft lead buckshot. It is tapped started like a muzzle loading black powder rifle then the buckshot is pushed through down the bore out the other end using an appropriate cleaning rod. Sometimes chrome lining slightly reduces the bore diameter. Just passing it forward.

Not for me, there are few thing I put down my barrels, usually lead sometimes even a clean rod or bore snake. I buy proper tools if there is a need or pay someone with them if that is impractical.

 

[Member 34319]

Chrome lining doesn't mean better precision. Usually the opposite. It is used as a way to prolong the barrels life. It is was a military thing for longevity. Since military rifles would likely actually see the amount of rounds that could hurt any other type of barrel.

For personal use, it is not needed in my eyes.

Melonite or salt nitride is perfectly acceptable. As is plain old phosphated CMV.

 

[titsonritz]

Chrome lining doesn't mean better precision. Usually the opposite. It is used as a way to prolong the barrels life. It is was a military thing for longevity. Since military rifles would likely actually see the amount of rounds that could hurt any other type of barrel.

For personal use, it is not needed in my eyes.

Melonite or salt nitride is perfectly acceptable. As is plain old phosphated CMV.

Chrome lining has nothing to do with precision. A barrel is either well made or is not, no lining or surface treatment will fix it. As you mentioned chrome lining is for longevity of barrel life through heavy fire. I doubt we'll ever see a Melonite SAW barrel.

 

[Member 34319]

Chrome lining has nothing to do with precision. A barrel is either well made or is not, no lining or surface treatment will fix it. As you mentioned chrome lining is for longevity of barrel life through heavy fire. I doubt we'll ever see a Melonite SAW barrel.

I stated that chrome lining can be less precise as it can have different thickness throughout.

From a personal experience, I've never witnessed a chrome lined barrel shoot as well as one that is not.

I'm no expert though. So I'm just talking to talk really.

 

[titsonritz]

I stated that chrome lining can be less precise as it can have different thickness throughout.

From a personal experience, I've never witnessed a chrome lined barrel shoot as well as one that is not.

I'm no expert though. So I'm just talking to talk really.

I was agreeing with you. A Melonite, Tennifer, QPQ, salt nitride, etc will always have a more consistent finish as it does not build up like chrome and will not dimensionally change the barrel while chrome is a lining and will. Another thing, SS cannot be chrome lined (it would defeat the purpose anyway) but it can be Melonited. Just keep in mind, if you kill barrels chrome cannot be beat for longevity.
https://ndiastorage.blob.core.usgovcloudapi.net/ndia/2002/gun/waterfield.pdf

But if you think chrome lining can't be accurate, go research the shooting by a guy called Molon and what did with a Colt SOCOM barrel.

 

[DirectDrive]

Wow, some wacky info in this thread.
I hope the OP isn't damaged for life.
CMV (Chrome Moly Vanadium) is the steel alloy. Does not indicate chrome lining.
I'm a stainless steel and/or Melonite guy guy....not into chrome lining.
For a blaster, chrome lining might not be a bad thing.

OP, the barrel in post #1 reads like an entry-level barrel.
But if it's just for a pistol, probably not a big deal.

 

[ron]

Chrome lined barrels can be accurate. I own one. That being said
competition AR Highpower shooters do not use chrome lined barrels.
The most popular ones for Highpower Competition are SS.

 

[bsa1917hunter]

Chrome lined barrels can be accurate. I own one. That being said
competition AR Highpower shooters do not use chrome lined barrels.
The most popular ones for Highpower Competition are SS.

All of mine are SS.

 

[MrMillspecer]

Mine have a CL stamped on the barrels that are chrome lined. And they are plenty accurate.

Melonite is a good one as well.

Oops I lied the Daniel Defense doesn't put CL on theirs.