What is so special about 17-4?

[Nitrox]

Can someone explain why someone would want to spend a disproportionate amount of money on a barrel made from this material?

[Hoplophile]

Longevity. If a 17-4 barrel cost 3x a normal 416R barrel but has 4 or 5 times the service life then it is a cost effective option for people who shoot enough that burning out a barrel or three every year is a problem.

[TigerStripe]

What do they cost?


TS

[Hoplophile]

What do they cost?


TS

Noveske doesn't sell the barrels alone, only as part of a complete upper. But the difference in price between an upper with the 17-4 barrel is about $600 so I can guess that they are about $1k depending on length, profile, etc.

[JLM]

TS, check his site for complete setup prices. I believe they are on there.

[TigerStripe]

Cool, thanks guys!

TS

[JLM]

Longevity. If a 17-4 barrel cost 3x a normal 416R barrel but has 4 or 5 times the service life then it is a cost effective option for people who shoot enough that burning out a barrel or three every year is a problem.

I'm not so sure I buy the 'longevity' claims made for this material. I've been led to believe that ANY precipiation hardened steel is subject to weakening when exposed to temperatures above the temper point. A quick search revealed the following:

http://www.azom.com/details.asp?ArticleID=1175

Both martensitic and precipitation hardening families of stainless steels have high strengths achieved by thermal treatments; exposure of these grades at temperatures exceeding their heat treatment temperatures will result in permanent softening, so again these grades are seldom used at elevated temperatures.

I guess it would depend upon your particular application, but on the surface it would seem these types of materials would not be something you would want to use for sustained fire, where you could possibly exceed the temper point of the material. To me it looks like you have to keep it cool to avoid permanent softening of the material.

If anyone else has any more relevant technical data, feel free to chime in. This is an interesting subject.

[Hoplophile]

I'm not so sure I buy the 'longevity' claims made for this material. I've been led to believe that ANY precipiation hardened steel is subject to weakening when exposed to temperatures above the temper point. A quick search revealed the following:

Agreed. But so long as you keep it under the temper point it should have a longer service life than other steels. The temper point used on NRW's barrels is fairly high, as I recall.

[bigbore]

Agreed. But so long as you keep it under the temper point it should have a longer service life than other steels. The temper point used on NRW's barrels is fairly high, as I recall.

17-4 hardening temps start at 900(f), the higher the hardening temp, the softer the temper -- most barrels in the past were made to condition H1025, the last number of the condition is the tempering temperature... so condition H1050 17-4 was tempered at 1025.

Steel manufacturers do not recommend using 17-4 in applications that will subject it to exposure and soaking in the temperature range of about 700 to 900 degrees (f) -- but it is arguable if a rifle barrel "soaks" in that range long enough to be a real concern, some situations certainly could.

Steel manufacturers warn against using it in applications that will subject the steel to temperature within 50 degrees of the temper point, therefore a rifle barrel would have to be kept below 975(f) under all conditions, and that’s not gonna happen with a autoloader.


From what I’ve found it makes a great prop drive for ocean going vessels, because of its strength and corrosion resistance.

Grade 630 (or 17-4PH) is an "age hardening" steel -- its low tempering temperatures are great for stability and it can be made pretty hard. It has been used in the past by several different companies for barrels, but most drop it. I’ve talked barrel makers, steel manufacturers, and none recommended 17-4 for a rifle barrel. I wish someone could explain the benefits related to cost of 17-4 barrel over a chrome lined 4150 barrel? I keep hearing the “accuracy” argument, but a good chrome lined barrel is more than accurate enough for a “fighting” gun – meaning capable of 1 MOA with good ammo.



I want to buy 2 17-4 barrels
One chambered in 6.5x284 for a T2K. I will give it to a friend who is a long range high master. A Krieger chambered in 6.5x284 will last about 1000 rounds. If 17-4 is as good as advertised, it will be obvious in this application.
This is something that can be tracked and documented.

I want another barrel to take to Knob Creek. I want to put in an upper to pass around. Lets see how it looks after a weekend with thousands of rounds through it. With no fouling, it should be fine.

[SuicideHz]

17-4 barrels would be nice if you burn through three per year but not when you have to buy a complete upper or weapon with it. At that point, you might as well buy 5 barrels at a time from WOA or someone similar.

I believe K.L. Davis tried making this point not too long ago and then it came up again recently on TOS.