Any benefit to melonited gas tube?

[jet80tv]

I did a search and only came up with a passing reference to melonite coated gas tubes in a Spikes vs BCM vs DD who's better pissing match thread so any insight would help. What advantage would these have over stainless steel tubes? Thanks

[mvician]

Nothing that I can think of other than it being black for those that want that.

[Thomas M-4]

The gas tube is a consumable much like the gas rings.
Keep a spares and replace when it is needed.


Would like to add the inside of the gas key is chromed lined. meloniting the gas tube would would just wear out the gas key faster.

[munch520]

The gas tube is a consumable much like the gas rings.
Keep a spares and replace when it is needed.

Yep. If you're real curious though, I believe the AR dictionary would say for melonite see: nitrocarburizing.

[jet80tv]

Well from what I can see they are only a few bucks more so it might be worth it to get a couple.

[saddlerocker]

I think they were developed for 5.45 uppers that may be shooting corrosive ammo.

but they are cheap, and so are the regular ones, so just preference imo

[Dave_M]

If you're shooting corrosive ammo?

Other than that, no, I don't see much of a reason. Current gas tubes run a loooong time before needing replacement.

[crazymoose]

IIRC, gas tubes are made out of 17-4 stainless, which is already pretty tough and corrosion resistant. Never seen one wear out from normal use, and the kind of use that would melt one would melt a nitrided one, too.

I'm a big believer in nitriding barrels, but i think it's a gimmick on a gas tube.

[Littlelebowski]

If you're shooting corrosive ammo?

Other than that, no, I don't see much of a reason. Current gas tubes run a loooong time before needing replacement.

At about 17k rounds on mine, all corrosive. Rinsing with water works just fine.

[Dave_M]

At about 17k rounds on mine, all corrosive. Rinsing with water works just fine.

I never got into that 5.45 weirdness :D

Ok, so, zero reason at all.

[5pins]

I never got into that 5.45 weirdness :D

Ok, so, zero reason at all.

Considering how low the price is for 5.45 it's something I have thought about getting.

[WS6]

I dug into this, a bit. If the QPQ process is kept at or under 500*C, corrosion properties are only slightly worse than non-QPQ'ed 304 AISI SS. The hardness and fatigues trength, and abrasion/wear resistance is significantly improved, especially at higher temperatures. However, when you reach around 1000*F (which, I doubt one would, gas-tube temps, even in extremis, only hit a bit over half of that), the stress rupture life is significantly reduced.

Over-all, the benefits are a gas tube which handles hotter temperatures (in relation to its intended use) better, and should create less friction with either a chrome-lined, or QPQ (LMT) gas-key, for longer life before the end of the tube "mushroom" is abraded enough to lose seal, if ever.

[Iraqgunz]

Sweet. But, I don't think you will win the necropost award.


I dug into this, a bit. If the QPQ process is kept at or under 500*C, corrosion properties are only slightly worse than non-QPQ'ed 304 AISI SS. The hardness and fatigues trength, and abrasion/wear resistance is significantly improved, especially at higher temperatures. However, when you reach around 1000*F (which, I doubt one would, gas-tube temps, even in extremis, only hit a bit over half of that), the stress rupture life is significantly reduced.

Over-all, the benefits are a gas tube which handles hotter temperatures (in relation to its intended use) better, and should create less friction with either a chrome-lined, or QPQ (LMT) gas-key, for longer life before the end of the tube "mushroom" is abraded enough to lose seal, if ever.