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

[Cameron]

Considering the relatively low cost of quality stainless steel barrels, and the relatively high cost of the ammunition required to shoot one out; I think it makes sense to move away from chrome lined, double chrome lined, super tough coated barrel and basically get a quality SS barrel in all my ARs from now on...

The up side of SS for great accuracy and corrosion resistance certainly out way the longevity of a lined steel barrel.

Cameron

[Brahmzy]

Considering the relatively low cost of quality stainless steel barrels, and the relatively high cost of the ammunition required to shoot one out; I think it makes sense to move away from chrome lined, double chrome lined, super tough coated barrel and basically get a quality SS barrel in all my ARs from now on...

The up side of SS for great accuracy and corrosion resistance certainly out way the longevity of a lined steel barrel.

Cameron

Agreed. All my rifles have Noveske stainless barrels in 'em. Only wish they'd offer a few more contours and have them in stock. They've got lightweight 18's & 16's. But only the NST guys get the lightweight contours in the other sizes. Really would love a lightweight profile Noveske 5.56 10.5, 12.5 and 14.5 barrel. Had to pay a grip to send mine all away for dimpling when I'd just rather have bought 'em in a lightweight Noveske contoured/gassed config.

I know I'm definitely shooting less lately because of ammo prices.

[Ring]

just a BIG reminder.... MAKE SURE YOU CLEAN OUT ALL OF THE NITRIDING FROM THE BARREL!!!!!!

i took a 260 bbl for a buddy, told him how to clean it and told him to fallow my instructions to a T...

he says he did... we go out and he is running the same load i use, he is blowing 50% of the primers...

i ask if he is sure he cleaned it good... he says yes....

i take it home and run a tight wet patch down it... real slow... i can feel the 1st 4" of the bbl by the chamber as rough...

so i re-scrub with a tight brush and use the JB bore compound untill i feel it smooth out...

take back to his house and he puts 20 shots threw it and all is fine, no psi signs....

but now he has to order a new ejector since it was so hot before it broke the ejector pin...

[TrenchArtisan]

I don't see what the harm would be in meloniting the BCG.
Its true that melonite isn't magic that turns low quality metal into uber milspec unobtanium--but as long as the barrel extension and bolt are both made of high quality metal with similar hardnesses before being treated, they should be same or similar hardnesses after melonite treatment, right?

[another-bill]

Here is a test from Louisiana Shooters with a Colt 6920 and a S&W Sport, well documented. The S&W Sport isn't too bad, IMHO.

http://www.ar15.com/forums/t_3_118/5...son_Study.html





Bill

[Magic_Salad0892]

I was under the impression that nitride treating a stainless barrel was bad.

Carbon steel is ideal for a nitride treatment.

Am I right?

[GrumpyM4]

I was under the impression that nitride treating a stainless barrel was bad.

Carbon steel is ideal for a nitride treatment.

Am I right?

Not necessarily "bad", just "different".

The hardness, penetration depth, and corrosion resistance of nitriding is dependent on the alloy of the steel being processed.

Nitriding will penetrate deeper into low alloy carbon steels, have corrosion resistance that beats chrome hands down, but will have a somewhat lower Rc hardness. It will still have the much lower coeficient of friction and be very slick compared to chrome, which will make up for the lower hardness in the bore.

Higher alloy steels will not allow the nitriding to penetrate quite as deep, but will be much harder, have a very low CoF (i.e. very slick), and still have the outstanding corrosion protection.

Stainless is where things get a little weird. Stainless (or Corrosion Resistent Steel = CRES according to govt. work) is a very high alloy steel which gives it the superb corrosion resistance in its normal state. When nitrided, the process doesn't penetrate as deep as it does with any other steel, it can reach Rc hardness levels in the 70s, and is super slick. The downside is that it can actually reduce the corrosion resistance a slight amount.

So, depending on how the end user looks at things, each steel has its own properties that may or may not provide what someone wants. Each has their own benifits/detractions.

I prefer using high quality alloy barrels (CHF if possible) that have been QPQ nitrided to gain extra penetration depth. The nitride very hard, are super slick(very low CoF, especially when polished prior to nitriding), and have outstanding corrosion protection.

The benifits of nitriding, in my mind, far outweigh chrome lining in all aspects, and for all grades of steel. Given how corrosion resistant nitriding is, the minor step down in corrosion protection on nitrided stainless is virtually a non-issue. The nitriding doesn't make stainless steel rust like untreated steel, it simply brings the resistance down to the level of normal nitriding, which is still head and shoulders above chrome lining, nickel plating, etc.

[sinlessorrow]

So tell me if I have this right, Nitriding does increase the rifling life in the barrel but it will not decrease gas port erosion?

[GrumpyM4]

So tell me if I have this right, Nitriding does increase the rifling life in the barrel but it will not decrease gas port erosion?

To be honest, I don't know.

I would make an educated guess that were the gas port drilled before nitriding, then yes, having the gas port walls strenghtened in such a manner would in fact increase the amount of time it would take for the port to enlarge to an unacceptable level.

I also suspect that the wear pattern in a nitrided barrel would be a bit different then in a non nitrided barrel.

Of course if the port is drilled post nitriding, all bets are off.

[Ring]

So tell me if I have this right, Nitriding does increase the rifling life in the barrel but it will not decrease gas port erosion?

Borescope Inspection After 1000 Round Full Auto Test
http://www.superiorbarrels.com/Barre...20test/SBs.htm

"
The gas port on this barrel also exhibits an erosion anomaly. As stated above, the erosion progression is normally an inverted V. However, this barrel shows tapering erosion, starting at the top. The inverted V has a flat, and the erosion is estimated to be about half the depth of the untreated barrel and not exhibiting roughened edges to the degree normally seen. Refer to diagram below."