Nitride Treated Barrels?

[Mjolnir]

My interest is peaked.........

I just read some articles about a 600 yard benchrester named Joel Kendrick that has been doing a good deal of experimenting with salt bath nitride. Found this link:

http://mminitriding.com/nitriding.htm

So here's a question, what type of test cases would be a good way to prove this out some more? Suggestions?

I'm not sure this could compete with a chrome-lined, CMV barrel. Where I see the real potential is in applications currently filled by stainless barrels.

I have to admit it would be a very tempting idea to be able to offer a CM barrel that offers better corrosion resistance than typical 416 or 410. But my real concern is throat life. One of the main benefits of some of the 416SS alternatives is increased accuracy life, being that this class of stainless still rusts. So either way coatings are necessary. I wonder how much of an increase in life could be expected through the use of salt bath nitriding when compared to some of the harder stainless barrels that are available.

(edited to complete the question)

I think it works with both ferrous (chromoly) and non-ferrous (stainless) alloys. The effects are greater with ferrous alloys.

Good question. I'm not sure of the answer. I do know that Noveske has ceased production of his superb 17-4 PH barrels due to tool wear and cost ($1,000 per barrel). Comparing that type of barrel to one of he same nitrocarburized vs. one of his chromoly barrels and one that is nitrocarburized would be interesting. Actually, several of each from different verified, documented batches would be required. A high temperature abrasion test could substitute (to an extent) the cost, time and effort of test barrels.

[dewatters]

FWIW: The barrels on Stoner 63 were nitrided. This came out in Stoner's testimony before the Ichord Subcommittee.

I have a copy of an old .mil report where nitriding and chrome-lining was compared for barrels in high cyclic rate weapons. Chroming was considered superior, but noted that chrome over a nitrided barrel was better yet.

[Kevin_J]

FWIW: The barrels on Stoner 63 were nitrided. This came out in Stoner's testimony before the Ichord Subcommittee.

I have a copy of a an old .mil report where nitriding and chrome-lining was compared for barrels in high cyclic rate weapons. Chroming was considered superior, but noted that chrome over a nitrided barrel was better yet.

I'd love to read that report if your willing to share. I think the point "High Cyclic Rate" might end up being where the field starts to split. All of the favorable reports I've read so far, sans one from LWRC, has been related to long gun like usage. My hunch is that favorable results will probably fall somewhere in the middle of 249 like usage and BR.

My feeling is that setting up the use-cases and designing the tests around those intended uses is the key to this. On a side note, some folks up here are discussing a basic test initially just to look at accuracy degradation over round count on a single barrel. That at least will tell us if it's worth pursuing further.

What I'd really be interested in knowing is the testing that companies like Sig and LWRC did. I imagine the outcomes of those tests we're favorable based on the decisions they've made.

[Mjolnir]

FWIW: The barrels on Stoner 63 were nitrided. This came out in Stoner's testimony before the Ichord Subcommittee.

I have a copy of a an old .mil report where nitriding and chrome-lining was compared for barrels in high cyclic rate weapons. Chroming was considered superior, but noted that chrome over a nitrided barrel was better yet.

I'd be very interested in reading that article. I know the nitriding process has progressed over the years to a very large degree. I'm not sure how far chrome plating has - or more accurately to what extent.

Personally, I like the concept of cold hammer forgied chromoly, nitrocarburized, micropolished then hard chromed. Of course, I'm prone to overkill as well.

[Bushmaster-M4A3]

I think Sig 556 rifles all have nitrided barrel, and there was some discussion over why Sig didn't do chromelining that we're so used to. Sig Sauer response was simply that nitriding is better, and it's used in original Swiss 55x barrels.

[Littlelebowski]

Nitride is a not a coating, but a metal treatment which increases surface hardness, corrosion resistance, with no degraded accuracy like chrome lining.

Just because a barrel's chrome lined, does not mean it's inaccurate or less accurate per se than a steel barrel.. My old FN SPR shoots (sold it to a friend) right around .25 MOA with FGMM.

[RogerinTPA]

I'd go with a chrome lined, cold hammer forged barrel, or a Noveske, since it has nearly double the chrome lining, over something that I would consider "experimental" since there is no "standard" in it's application, yet. It would be "mystery meat" as to whether you got a "quality" product. Not enough data available on the subject to convince me otherwise.

[dewatters]

I'd love to read that report if your willing to share. I think the point "High Cyclic Rate" might end up being where the field starts to split.

The 1968 report is a summary of the available technology and emerging research in barrel construction for automatic weapons.

Materials for Small-Arms Gun Barrels

[Kevin_J]

The 1968 report is a summary of the available technology and emerging research in barrel construction for automatic weapons.

Materials for Small-Arms Gun Barrels

Thanks! That's an interesting read.

[Mjolnir]

I'd go with a chrome lined, cold hammer forged barrel, or a Noveske, since it has nearly double the chrome lining, over something that I would consider "experimental" since there is no "standard" in it's application, yet. It would be "mystery meat" as to whether you got a "quality" product. Not enough data available on the subject to convince me otherwise.

While I, too, adore Noveske's products and cold hammer forging I'd not call nitrocarburization "experimental". Look to Europe and you'll find nearly ALL of their barrels treated as such including ACCURACY INTERNATIONAL. I got that DIRECTLY from their rep at SHOT 2006.

Sad thing is, I convinced him to sell me an AWP (I told him why I thought the SPR A3G was the "best" bolt gun and we had a long, technical discussion) for $5,500 with an extra barrel. I never followed up and I kick myself now as they go for $7k and barrels are $900...

If I ever decide to build another bolt gun it will have a Mike Rock barrel that will be nitrocarburized. Now granted, I don't and won't play with it enough to make a difference and neither will 99.9% of the rest of us but I'm fascinated with making things LAST. "FOREVER" if at all possible.