Nitriding Rifles

Has anyone had this done or had any thoughts about it?
This is more intended as a discussion thread as it seems a pretty cool idea kind of doing a more hardy cerakote job but with a few possible extra benefits.

Benefits I see as possible now are:
-Black Coating and increased corrosion resistance
-Natural lubricity possible smoothness to actions/increased barrel velocities
-Increased durability through surface hardening/possible increased barrel life

Cons
-Possibly stress inducing
-Possibly unavailable/ expensive

It requires the use of special steels and has to be done during the manufacturing process. Can't be done afterwards.

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Originally Posted by gundoc

It requires the use of special steels and has to be done during the manufacturing process. Can't be done afterwards.

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Are you sure about that? I've read multiple accounts of people in the US sending off finished rifle barrels for salt-bath nitriding (specifically ferritic nitrocarburizing according to Google), or 'melonite'.

I see www.heat-treat.co.nz seems to offer nitriding, carbonitriding and "Black corrosion resistant nitriding". I've never contacted them though.

Quote:

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Originally Posted by gundoc

It requires the use of special steels and has to be done during the manufacturing process. Can't be done afterwards.

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Many common tools steels like 4140 and P20 can be nitrided and it is done after the final machining, fitting and polishing process.

The biggest benefit is the lack of distortion which generally requires no more than a light polish afterwards. Surface hardness is around 60HRC from memory but is only a few thou deep. Not easily reworked.

I could see it being excellent for actions as you would really limit any wear between the parts especially around the bolt lugs.

Colour can be a bit hit & miss, its not expensive and done in Auckland by heat treatments.

I think there are two things here, one is colour case Harding and the other is nitride , on 4140 steel it hardens just the surface of the parts. This is what I had done to my Sharps action and breech block, It comes out grey and can still be black oxide.

I thought Dean Maisey does it

I've had a few non-gun things done and it's good stuff. Good process in terms of wear. Apparently good in terms of corrosion resistance but haven't really tried to find out.

Three different kinds of nitriding - gas, salt and plasma. What you choose will be down to who does it at a good price and your metals. Basically nitriding is an industrial way of case hardening steels without risking warping. Like bluing, it's not going to hide any imperfections, and the better the surface finish you have going into the process the nicer it'll look coming out. Usually comes jet black. Also quite cheap for what you get. Don't know how it works in NZ but industry standard elsewhere is you pay by the kg of material being done. Downside is that some companies are doing their nitriding for industrial machinery and aren't super concerned about finish appearance as long as they're nitrided - will just come down to who is doing it. Also don't plan on doing any metal alterations after nitriding like drilling, engraving, finish reaming a chamber etc - grinding's about the only thing that will go through a nitrided finish.

No idea what it does to stuff like solders or non-iron based metals. Best to treat it like a gun going in for a hot bluing and remove anything that isn't steel and polish/degrease before it goes in for treatment.

Nitriding has been common practice in the AR/pistol/modern semi auto world for ages now. The selling point for barrels, is it offers similar benefits to chrome lining, without distorting bore uniformity and putting rough patches in the lands. So you get improved corrosion resistance, increased barrel life, natural lubricity and easier clean up. I don't know why it isn't applied more widely in the firearm industry. It just makes sense to do it to bolt action rifles and shotguns.