S&W Melonite coated barrel vs Noveske chrome lined barrel.

[Boss Hogg]

With the improvements in metallurgy and coatings in recent years, I predict the AR market is going to see a gradual move away from chrome lining. If you can get similar barrel life, and a 30 to 50% improvement in accuracy, what's not to like?

[m4brian]

Any tests to demonstrate the difference in accuracy?

[rsilvers]

Not that I know of.

I am not a big believer in chrome harming accuracy much. But it can't help, that is for sure.

[m4brian]

30-50% quoted is a heck of a difference IF we mean reducing 2" groups to 1-1.4" at 100 yards. Nothing to sneeze at for longer distances, although in combat shooting likely not a big deal. I'm from Missouri on this one.

[Dirtyboy333]

With the improvements in metallurgy and coatings in recent years, I predict the AR market is going to see a gradual move away from chrome lining. If you can get similar barrel life, and a 30 to 50% improvement in accuracy, what's not to like?

I agree and the think the moving has already started.

Also, I won't claim any accuracy % differences but it has definately been my experience that unlined barrels shoot better. Of course this is with a small sample (maybe 15 lined, 8 unlined) and the only constant variable was that the same ammo was used.

The accuracy difference wouldnt normally be a big deal but when ringing my 2/3 IDPA steel over 400yards it's pretty significant.

BTW: is the MK12 CL CMV or stainless?

[Fabius]

The Smith and Wesson barrels also have 5R rifling, which is supposed to provide a better gas seal for improved velocity. The lands on 5R rifling are contoured, which reduces fouling and improves accuracy. I suspect that the differences are relatively small, but the combination of increased barrel life, increased velocity and greater accuracy is nice.

[m4brian]

It would be nice to see this Smith with a lightweight barrel profile. It would be very lightweight.

Who else is using this barrel treatment now, moving away from chrome?

[Ring]

either way ill SBN this barrel, but what barrel should i get?

so... should i buy hammer forged 1/7
http://www.bravocompanyusa.com/BCM-B...d-16%20bfh.htm

or

or SS 1/8
http://www.bravocompanyusa.com/BCM-S...16%20ss410.htm

[Fabius]

It would be nice to see this Smith with a lightweight barrel profile. It would be very lightweight.

Who else is using this barrel treatment now, moving away from chrome?

Sig uses a nitride treated barrel on the 550 series including the 556, Bushmaster on the ACR, LWRC and AAC have also gone to nitride treatment for barrels. DS Arms uses a nitride treated barrel on its ZM4 carbine (flattop AR) and the SA58 CTC (FAL) rifle.

[SomeOtherGuy]

Sig uses a nitride treated barrel on the 550 series including the 556, Bushmaster on the ACR, LWRC and AAC have also gone to nitride treatment for barrels. DS Arms uses a nitride treated barrel on its ZM4 carbine (flattop AR) and the SA58 CTC (FAL) rifle.

CMMG's "WASP" treatment is also some form of nitrocarburizing.

Just to summarize and add a few, the list of currently marketed ARs or uppers with some form of nitrocarburizing treatment seems to be:
S&W M&P15 "Sport" model
CMMG - LE Series with WASP treatment
DS Arms (most ZM4 models and ZM4 uppers, but they also offer plain CM and chrome-lined on certain styles)
LWRC
POF-USA
AAC
Adams Arms (uppers)
Huldra Arms (rifles and uppers with chrome-moly barrels {not stainless})
Bushmaster ACR (no other models)
Sig - 550-556
Superior Barrels with "hard blue" (uppers and barrels) {http://www.superiorbarrels.com/}

From the list above it seems that this treatment is used by inexpensive models on the one hand (S&W, CMMG, DSA) and boutique more expensive models on the other hand (all others), and as far as I know is not currently used on a mid to high end upper in an ordinary DI AR-15 configuration, with the sole exception of the uppers from Superior Barrels, on which I have no reputational information.

Fabius, I couldn't find any information about an "SA58 CTC" on DSA's website or on google. I know that DSA had been offering nitride treated L1A1 barrels for a brief period of time, but apparently not right now. Do you have any more information on this model? Most of the SA58 models have a 4150 steel barrel that is cryo treated but not, to my knowledge, given any surface treatment like chrome or nitriding.