AR15 Barrels: Chrome-Moly vs. Chrome Lined

[Digex2]

Could someone explain to me the difference between a chrome-moly barrel and a chrome lined one?

 

[Jim Watson]

Chrome-moly means chromium molybdenum alloy steel, the usual material for gun barrels and other parts (excepting things like aluminum AR recievers, of course.)

Chrome lined means that the bore and chamber of a barrel (probably made out of chrome moly alloy to start with) has been plated with metallic chromium. It is more heat, chemical, erosion and abrasion resistant than bare chrome moly steel or even stainless. Chrome lined barrels last much longer than unlined barrels, so if you are conducting a war or otherwise blasting off a lot of ammo with moderate accuracy requirments, it is desirable.

However, it is not possible to do a perfectly uniform job of plating. You won't find many target shooters using chrome lined barrels. They put up with the shorter life of chrome moly (or stainless) barrels to get top accuracy.

 

[Bartholomew Roberts]

It is also worth noting that while a good chrome-moly barrel will usually be more accurate than the same barrel with chrome-lining for the reasons mentioned, a good chrome-lined barrel is often capable of 1MOA accuracy and occasionally better.

If your accuracy requirements are less demanding than sub-MOA, chrome offers some advantages.

 

[usp_fan]

Depending on your barrel twist, load, and firing pattern, you can expect to get at least 2x the life from a Chrome-lined AR barrel. They also have a Chrome-lined chamber--critical in a grab and go rifle as it is much less likely to rust or suffer from neglect over time.

Surplus military A2 and A1 barrels are available. Commercially, Bushmaster and Colt Barrels can be had in a variety of configurations with chrome lining. I believe Rock River Arms is starting to sell this option as well.

--usp_fan

 

[ARperson]

In my opinion, the difference in accuracy between a chromed and non-chromed barrel are smaller than most average plinkers are going to notice. Since I've been able to get what I consider very good accuracy out of the chromed Bushy (4 of 5 shots touching at 100 yds, iron sights), I'll settle for the "less" accurate and easier-to-clean barrel.

 

[dbshabo]

I thought a chrome lined barrel had the chromium molecules introduced into the barrel steel by electrolysis of some sort. I don't think the bore is plated like a car bumper is. Is this correct?

Shabo

 

[Omaha-BeenGlockin]

Chrome lined is the only was to go for a serious SHTF weapon------if you want a targeter or plinker-- non-lined is just fine.

 

[MrAcheson]

I don't think the bore is plated like a car bumper is. Is this correct?

Yes. When gun people talk about chroming we mean hard chrome which is a tool and die treatment. When car people talk about it they mean nickel chroming which is softer and different. You can get a lot out of googling them.

 

[mrapathy2000]

who the heck makes hardchrome lined barrels anymore?

just got RRA lower and looking for parts to build. looks like all anyone has is either stainless of chrome moly. would like 5.56 chamber with chrome line not moly.

 

[hanko]

who the heck makes hardchrome lined barrels anymore?

Bushmaster, RRA (as an option), JT or M&A (can't remember which one), and Oly (also optional). A significant advantage of a chrome lined barrel is that the chamber uses a 5.56 chamber...far less particular in feeding, and a necessity if you're shooting surplus ammo.

-hanko

 

[GLOCKT]

I shoot a 24" V-match Bushy barrel in local shoots and it is chrome lined.
At 600 yards it doesn't effect hitting paper 8-9-10-X rings,thats from the prone position.My off-hand is awful-hand so to say.
Chrome lining doesn't seem to effect the travel of my 68gr HPBT LC ammo I shoot at this distance.
Just makes for easy clean-up.

 

[mrapathy2000]

they all hide the chrome lined barrel on theyre website if they have it at all or obscure it. 1 freakin option or other crap. like pulling teeth to find it and put info to figure out price. while they price out chrome moly and stainless versions with various uppers and other parts.

cannot get to bushmaster website timed out all day long.