Salt Bath Nitride?

D

disseminator

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So I am building my first custom rifle for myself. It will use a Remington 700 Action and a Shilen short chambered 7mm08 barrel in the factory profile.

I already have these.

I was wondering what you Gunsmiths think about Nitriding a hunting rifle and at what stage of assembly should this occur?

Should the parts all be Nitrided before being assembled so that the Nitride can reach every part? Assuming that to be the case, can anyone give any pros or cons of this plan or even a good place to have it done?

Thanks
 
Any finish goes on the barreled action after the barrel is installed and fully chambered. You put an empty case in the chamber and lightly tap a cast bullet into the muzzle. Small parts(triggers and such) get done separately. And no springs at all.
Metal finishing shops from the Yellow Pages that will do firearms are the way to go. Where you are matters. Sending the thing across the country for finishing is kind of daft when a local metal finisher can do it.
Nitriding is a heat treating thing. Basically a chemical case hardening thing. Black phosphating(same idea as Parkerizing but using different chemicals) works really well for hunting rifles. Did my .243 over 30 years ago and it's still pretty. Didn't matter that the bore got phosphated either.
 
Thanks for your reply.

The reason I ask about whether the gun should be assembled or not for Nitriding is that apparently a lot of shooters Nitride the inside of the chamber and barrel which increases the life of the barrel substantially. I have Nitrided barrels on two AR rifles and they are Nitrided inside, outside, on the treading, everywhere. Same thing with the BCG's that are Nitrided.

Apparently, the Nitriding process adds no dimension to the metal and so is better than some other methods for that reason.

d.
 
I'm not sure the barrel is supposed to be plugged when nitriding. We don't plug our barrels when bluing because it doesn't add any significant thickness and it helps protect the barrel inside and out.

As I understand it, nitriding also adds a very negligible amount and is beneficial inside the bore as it increases hardness, lubricity and corrosion resistance, leading to increased barrel length and some reports of increased bullet velocity
 
Hi. Don't think it matters if the inside gets done. It has made no difference at all with the phosphating in mine. And that does add a tick that'd get 'polished' flat and smooth with the first shot. Only thing is that you won't have that nice shiney bore.
You wouldn't have the stock on in any case.
Seriously doubt it'd make much difference to barrel life. Although these guys who do it for a living say it increases wear and corrosion resistance.
http://www.blacknitride.com/whatis.html
Mind you, barrel life is rarely an issue at all. Takes a lot of shooting to wear out a barrel. And it's relative to what you're doing. A bench rest guy sees it differently than a varmint hunter.
 
Salt bath nitriding is a metallurgical surface hardening process. Coming out black is just a bonus style feature.

A local pistolsmith has learned the hard way that nitriding small parts can make them TOO hard and brittle, he has had to replace some extractors and ejectors. Best thing to do is to ask the vendor.
 
Surface treatment.

Good point on the small parts. I am looking at mostly the barreled action, maybe trigger guard, and bolt hood/handle.

I am gathering that this is not something regularly done? If I went with a more conventional finish like Black Oxide/Blueing, would that be done prior to final assembly or after making in the barrel and cutting with the finishing reamer?
 
Salt bath nitride is not commonly done in house because it uses some nasty chemicals and I have been told it takes place at over 900 degrees. Hot bluing is far more common.

When hot bluing a custom rifle, the barrel will be fitted and chambered to proper headspace. The barreled action will be polished and go into the blue tank as one piece. Your small parts will be separated of any pins and springs and blued in a basket.

Your final look with hot bluing reflects the final polish before bluing. Bead blasting and low grade polishing will result in a matte finish while finer polishing will produce a nice luster. Expect to pay more for higher polishing or do it yourself
 
That's for the information on Blueing.

In addition to the anti corrosion properties and, MAYBE, more barrel life which isn't really an issue in a hunting rifle anyways, a little story on the quality of Nitride:

I was installing a new gas block onto my AR15 which has a fully nitrided barrel. I broke three bits trying to put a dimple into the barrel for the gas block screw. Then got a high $$ bit and got through. With the standard bits there was hardly a scratch.

So, when building my first rifle I though: get the best coating you can.
 
Nitriding has a case hardening effect which likely made the metal harder than a standard high speed steel drill, leading to you breaking yours.

I think high luster bluing is one of the most beautiful firearm finishes over a nice wood stock, but there are more durable finishes and finishes that suit synthetic stocks better. A base layer of parkerizing with a top coat of cerakote is known to be very durable
 
There is more than one kind of nitriding.Frankly,I'm not knowledgable about how they all are done.
Mold ejector pins are H-13 hotwork tool steel that is nitrided .It has a very hard case maybe .010 to .015 deep,and its near Rockwell 60.The crankshaft of my old 63 Volvo B-18 engine was nitrided.. It could be ground undersize,so it had some depth.
All of those gold colored drills and end mills are titanium nitrided.That is dimensionally thin,I can't give a number.A few I/10th thousandth? Its about 93 Rockwell C and can take high heat.The substrate,of course,is what it is.
There is gas nitriding,salt bath..I don't know what else.Some of it requires playing with hot cyanide.Maybe I have heard of a boron nitride lately? I don't know about it.
I would guess(I don't know) its titanium or boron nitriding for a barrel.
You might search up a vendor and call them.
Know what your barrel steel is.I suspect the barrel must be unfired.Any copper will mask the results
 
Call Club Custom guns. They can tell you anything you need to know about nitriding, and can have it done for you. They do great work.
 
Barrel steel does come into play, reaching back from reading on AR15.com I do believe 416 stainless is less suited to QPQ nitriding, which is salt bath. Nitriding actually changes the metal to a few mils deep if I remember and doesn't add extra material, it adds corrosion resistance and increases hardness. So it splits the difference between pure stainless and chrome lining. That being said I almost always hear about it related to AR's and don't really know anyone who uses it on a bolt action.

That being said I don't think it could hurt and if you like the color it gives go for it.
 
I have a few customers who have done this to their rifles (large case, high velocity cartridges). It all sounds really cool, but what erodes barrel steel is not friction, it is the high pressure/hightemperature gases during firing that vaporizes the metal. Two different rifles, 4 barrels, no notable difference in accurate barrel life. I know 4 barrels is not much of a sample, but you would think there would be some noticeable change in barrel life.
 
My ar barrel is nitrided inside n out. It has a dark black plum color. Easy to clean the bore too :o. 223 wylde chamber, it is accurate ;)
 
Scorch is correct. When a rifle is fired, the bullet does not move immediately, it sort of sits there thinking about moving. (Sort of like me when the wife wants something done.)

The powder continues to burn, producing hot gas that moves around the lazy bullet at very high speed (paging Signor Bernoulli!) and eroding the barrel in front of the chamber. Eventually, that results in the bullet skewing as it begins to move and the result is inaccuracy. No case hardening will reduce that effect by any significant amount, since the steel is burned, not worn, away. Use of some alloys, either for the whole barrel or as a full or partial liner will reduce that erosion, but the cost is prohibitive for a sporting rifle. Some military automatic weapons have such liners, made from an alloy called Stellite, but my Uncle (Sam, that is) has more money than I do.

Jim
 
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