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View Full Version : What is the best Finish/Coating/Bluing?


300magman
December 28, 2010, 07:26 PM
I'm looking at building a long range rifle using a Surgeon action, but I see they only come in chrome moly and are shipped in the white.

What would be the most durable way to treat the metal, to both last a lifetime and have no negatively affect on accuracy or the smoothness of bolt cycling?

And just incase I can't afford the best method....what is the cheapest method that will get the job done, somewhat well.


Any sugggestions are much appreciated.

Adrian
December 28, 2010, 08:43 PM
I'm not a metallurgist or a manufacturing engineer, just a bit of a dork, but...

Nitrocarburization ("nitriding", "Melonite", "Tenifer", etc) is extremely hard and almost unbelievably hard-wearing. I understand that you can get Vickers hardness numbers of about 700-1600HV, depending on your particular steel (most good steel is typically ~350-400HV) - files won't scratch them. Nitriding supposedly leaves no change in the dimensions of treated metal, so your bolt would be exactly as smooth as it was going in.

There are various titanium nitrides that are even harder (AlTiN can go as hard as ~3300HV or so, and TiCN can go to 4000HV), and there's always the diamond-like carbon coating out of IonBond (~3000 HV). These will add just a tiny bit of thickness, so your bolt may get microscopically tighter, but I doubt it would affect the smoothness of the pull. I'm not sure how hot the TiCN deposition process runs - it may ruin the steel in other ways - but I know that DLC is a popular aftermarket option for high-end pistols, and AlTiN isn't unheard of either. Both of these are pretty nice in that they're slightly porous and have really good "hold" on oil. I've handled pistols with both coatings, and they felt slick as Teflon.

If I wanted to be really neurotic, I might have an action nitrided and then run through the DLC process. I suspect it isn't out of your price range - you can find dealers who can have IonBond do their magic for about $250 for a pistol, so I can't imagine that a rifle action would cost much more than that. I don't know what nitriding runs, though.

Bogie
December 28, 2010, 09:48 PM
There is no magic finish.

IMHO, for lubricity, the best thing to pay attention to is the actual lubrication used. We've been looking at some greases, and we like some, but NONE are "all-around" performers... One that we -really- like is great for matches/competition and general practice where you'll be shooting a lot, but I wouldn't want to use it in a "tactical" environment where it could end up attracting crud... But on a clean gun, it's just slicker than owl snot...

JiminTexas
December 28, 2010, 10:59 PM
If you want to get practical and reasonable (on the price that is) Dura Coat is the way to go. You can apply it yourself. It is best to use a compressor and an airbrush, but they have another system that you can buy. An airbrush from Harbor Freight will work just fine and costs less than $25. It is inexpensive, less than $100 for enough to do a couple of rifles. you can even have your rifle match your pistol. It can be applied in patterns. It is durable. It must be bead blasted off. Sanding doesn't work very well. check it out.

http://www.duracoat-firearm-finishes.com/

warbirdlover
December 28, 2010, 11:36 PM
I AM a (retired) metallurgist and Adrian is correct. The new nitriding coatings (especially to stainless guns) is the best it gets. TC has that option on their top stainless guns and so does Remington. Not sure about anyone else.

Jimro
December 29, 2010, 02:07 AM
I am fond of manganese phosphate "parkerizing" for hard use rifles. But if that isn't your cup of tea I understand.

Jimro

Scorch
December 29, 2010, 03:35 AM
Nitriding is good, but expensive, as are TiN, the exotic "diamond" finishes, and hard chromes. Most finishes will add dimension to your parts, nitriding will not.

For cheap and effective, there is GunKote, Dura Coat, and the Brownells' bake-on finishes. Parkerizing, surprisingly, is a fairly good low-tech finish. Electroless nickel is also very durable and a good corrosion barrier.

madcratebuilder
December 29, 2010, 09:29 AM
And just incase I can't afford the best method....what is the cheapest method that will get the job done, somewhat well.

Parkerizing is your best bet. Even the best bake-on finishes can and do get chips. Nitride if you can justify the cost.

300magman
January 4, 2011, 09:44 AM
DuraCoat looks very easy, I think I might give that a try on one of my older guns that needs some restoration. But I don't know about using it on my target action, I think the tolerances are virtually at the minimum, so even the slight increase in thickness could be a problem.

Parkerizing is harder to find good information on, and looks to be overly involved with too many chemicals for my comfort level of "at home" projects.


I may have to look into the Nitrocarburization. Can anyone recommend a shop, from their own personal experience, that applies this process.
And if the process doesn't increase dimensions (at all) could it be applied to a barrel (both inside & out) to produce a very hard, long wearing bore? Or would the process change the surface texture, perhaps making it rough and negatively affecting accuracy?