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Nitrocarburizing a rifle bbl

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So after I realized my Benchmark 7WSM bbl was an absolute hammer, I decided to have it "immortalized" with the nitrocarburizing process known as melonite salt bath treating. I had 150 rounds down the tube when I sent it off to get treated which I would call the absolute max round count for a bbl burner like the 7WSM. After getting the bbl back, I followed the break in process recommended by a friend which involved lapping the bbl with valve grinding compound. After one process of that I went and fired 15 rounds and came back to the shop, cleaned it, and went after it again with the lapping compound. I then loaded up 15 rounds to do another load development post treating. Turns out I am at the same speed as before coating, with the same accuracy, with 1 less grain of powder. Needless to say, I'm pretty happy with the job Joel Kendrick did on the bbl and will be sending him every bbl I do in the future. I'm expecting to increase bbl life by AT LEAST 50% with most reporting gains of 100% which means I just turned my 1600 round bbl into a 3200 + round bbl. Before the bbl was sent to Joel we spiral fluted it with 8 flutes in a 360* twist. I'll post some pics of the bbl (a 28" Benchmark bbl) soon. The group pictured below was shot with 168gr Berger VLD's @ 3075 fps. I'll say the accuracy is there. :shock: I didn't measure the group yet, but I'd guess it under .25 MOA by a bit.

2010-04-03211923.jpg

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So after I realized my Benchmark 7WSM bbl was an absolute hammer, I decided to have it "immortalized" with the nitrocarburizing process known as melonite salt bath treating. I had 150 rounds down the tube when I sent it off to get treated which I would call the absolute max round count for a bbl burner like the 7WSM. After getting the bbl back, I followed the break in process recommended by a friend which involved lapping the bbl with valve grinding compound. After one process of that I went and fired 15 rounds and came back to the shop, cleaned it, and went after it again with the lapping compound. I then loaded up 15 rounds to do another load development post treating. Turns out I am at the same speed as before coating, with the same accuracy, with 1 less grain of powder. Needless to say, I'm pretty happy with the job Joel Kendrick did on the bbl and will be sending him every bbl I do in the future. I'm expecting to increase bbl life by AT LEAST 50% with most reporting gains of 100% which means I just turned my 1600 round bbl into a 3200 + round bbl. Before the bbl was sent to Joel we spiral fluted it with 8 flutes in a 360* twist. I'll post some pics of the bbl (a 28" Benchmark bbl) soon. The group pictured below was shot with 168gr Berger VLD's @ 3075 fps. I'll say the accuracy is there. :shock: I didn't measure the group yet, but I'd guess it under .25 MOA by a bit.

2010-04-03211923.jpg

Very interested to see how this works out. Please post updates.

Now get out there and put 3k rounds through that sucker! :D

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I'm working on it! I also have one of the new remote video target spotting systems I have to do a review on. It's a pretty cool product. Let's you set up a small video camera near the target and has a 7" monitor for you to be able to see your hits from. It's a 2500 yard unit which is really helpful when shooting from beyond 1000 yards in being able to see your hits. It will even resolve .17 cal bullet holes in paper that you can see from over a mile away, not that any .17 will make it that far. ;) I'll post a bit on it in my dealer forum soon.

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Please do. I have been looking at video spotting for a couple of years now, but there weren't any finished systems and I did not trust myself to assemble one out of catalog parts.

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Would this be a cost effective way to conserve the life of most "barrel burner" caliber's ? Say a 22-250 or something else along those lines in a non competition dedicated rifle ? Maybe an average varmit type rifle that someone wants to shoot the crap out of but not replace the barrel once a year ?

Basically, what type of application is this good for ? :D

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Would this be a cost effective way to conserve the life of most "barrel burner" caliber's ? Say a 22-250 or something else along those lines in a non competition dedicated rifle ? Maybe an average varmit type rifle that someone wants to shoot the crap out of but not replace the barrel once a year ?

Basically, what type of application is this good for ? :D

That is EXACTLY what it is good for. You can double, possibly triple the bbl life by having it melonite treated.

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Now that you mention it, I remember seeing some manufacturers are using that on their parts instead of hardchroming?

I think POF is the one I'm thinking of.

Somebody asked me how hot they have to get the material for the salt bath and I couldn't remember?

We had a couple pistols done in this and they are very hard for sure!

I've always wondered for pistols if you could nitride it and then hardchrome over that??

IIRR you can do stainless but not titanium.

Nick

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TiAlN is still much harder, and the nitro melonite treatment WILL wear off. I think Glock, and the M&P line are melonited. I'm not sure if it's even as durable as Ion Bond.

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It should be interesting to see how it really holds up... I've read several threads on this process that all sound encouraging. I did note one person on benchrest.com that seemed less than pleased, asking about whether Joel was going to also tell people about barrels turned into tomato stakes. Down @ FCNC in Sacramento I got a chance to talk with a couple fellers from back east who are both very good F/Open shooters... apparently a friend of theirs had a barrel that went T.U. after being treated. Granted, it's relatively few complaints against the seeming mass of favorable reports... but it's something to keep in mind anyway.

Monte

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I think Glock, and the M&P line are melonited. I'm not sure if it's even as durable as Ion Bond.

The Glock is tenifer'ed - but that's not the outer coating that you see. They parkerize it after the Tenifer (trademarked name for a particular salt bath process) - it's the park that you see wearing off on them...

Edit to add the tenifer detail - while similar, it would apparently have some differences in process with melonite, so it's probably not strictly correct to say that the Glock is melonited. I have no clue about the M&P, so...

Edited by XRe

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I think Glock, and the M&P line are melonited. I'm not sure if it's even as durable as Ion Bond.

The Glock is tenifer'ed - but that's not the outer coating that you see. They parkerize it after the Tenifer (trademarked name for a particular salt bath process) - it's the park that you see wearing off on them...

Edit to add the tenifer detail - while similar, it would apparently have some differences in process with melonite, so it's probably not strictly correct to say that the Glock is melonited. I have no clue about the M&P, so...

Trademarked name maybe for the nitrocarburizing Dave? You can change the name of it to anything, it's still the same process. Do some research on nitrocarburizing aka salt bathing. Talk to the people that DO IT for a living and ask them what it is. The M&P's are melonited in Ohio. Para Ordnance guns are being melonite treated right now with my friend. I think I'm going to have a few guns done it just to know what it's like. I can tell you this, I can't get a complete gun Ion Bonded for $125.00! If you like black, it may be the new thing.

To meet the growing needs with regard to wear and corrosion resistance, as well as the enhancement of the fatigue strength, great efforts were devoted to the development and launching of the TENIFER® process, which is also known worldwide under the trade names of TUFFTRIDE® and MELONITE®. This nitrocarburizing process has undergone continuous development with regard to its regenerability and ecology, and from year-to-year the number of applications is increasing on all 5 continents.

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It should be interesting to see how it really holds up... I've read several threads on this process that all sound encouraging. I did note one person on benchrest.com that seemed less than pleased, asking about whether Joel was going to also tell people about barrels turned into tomato stakes. Down @ FCNC in Sacramento I got a chance to talk with a couple fellers from back east who are both very good F/Open shooters... apparently a friend of theirs had a barrel that went T.U. after being treated. Granted, it's relatively few complaints against the seeming mass of favorable reports... but it's something to keep in mind anyway.

Monte

Monte,

Out East here where I am, a friend named John Whidden and crew have figured out that a few things may have to be done to a "used" bbl to make them shoot again. My bbl shot about an inch before performing the lapping process when I got it back. It's now shooting in the teens again. I have complete faith in Joel's process. If the bbl is good to begin with, it'll be good when he returns it.

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Trademarked name maybe for the nitrocarburizing Dave? You can change the name of it to anything, it's still the same process.

Bluing is bluing, but depending on how you perform the process, time per step, etc, etc, you get different results. So it is with any other chemical process, including nitrocarburizing. While the chemistry is similar, the process may differ in important (and proprietary) ways. Fundamentally similar, but...

The research I've done on it suggests that the Tenifer version of the process involves using cyanide salts in the bath, whereas the Melonite process does not (it's been conjectured that the EPA won't allow that practice on US soil). That would suggest "similar to, but not the same".

Nowhere did I say that Tenifer was not a nitrocarburizing process - you may have misread what I wrote... ;)

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John Whidden and crew have figured out that a few things may have to be done to a "used" bbl to make them shoot again. My bbl shot about an inch before performing the lapping process when I got it back. It's now shooting in the teens again. I have complete faith in Joel's process. If the bbl is good to begin with, it'll be good when he returns it.

So... are you going to share this info, or is it 'proprietary'?

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John Whidden and crew have figured out that a few things may have to be done to a "used" bbl to make them shoot again. My bbl shot about an inch before performing the lapping process when I got it back. It's now shooting in the teens again. I have complete faith in Joel's process. If the bbl is good to begin with, it'll be good when he returns it.

So... are you going to share this info, or is it 'proprietary'?

See post #1.

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Trademarked name maybe for the nitrocarburizing Dave? You can change the name of it to anything, it's still the same process.

Bluing is bluing, but depending on how you perform the process, time per step, etc, etc, you get different results. So it is with any other chemical process, including nitrocarburizing. While the chemistry is similar, the process may differ in important (and proprietary) ways. Fundamentally similar, but...

The research I've done on it suggests that the Tenifer version of the process involves using cyanide salts in the bath, whereas the Melonite process does not (it's been conjectured that the EPA won't allow that practice on US soil). That would suggest "similar to, but not the same".

Nowhere did I say that Tenifer was not a nitrocarburizing process - you may have misread what I wrote... ;)

The end product is the same, regardless of how you get there. The cyanide portion of your research is also incorrect. The factory doing the M&P work in Ohio is using a cyanide introduced process.

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See post #1.

I know. It's a little vague on that point ;)

Brand/grit of compound? Using patch over a bore brush, or the felt pellets made specifically for bore lapping, etc.? How long was each session in terms of how many strokes, how often replenishing the compound?

It also begs the question... if this process is supposed to be tough enough that a barrel can't be set back i.e. re-machined (according to the article in Precision Shooting), how does running some lapping compound over it have a meaningful impact, etc.?

Edited by milanuk

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Monte,

My understanding is the process leaves a fish scaling on the inside of the bore. If the bbl has been shot, specifically in the throat area, there may be some burnishing that allows this "film" to grab hold. John told me the more a bbl was shot, the more work you have to do on it to get it back. My 7WSM was at the brink of being too far gone with 150 rounds down the tube. Joel recommends no more than 50 rounds fired from any caliber.

I started out by cleaning the bore with some IOSSO on a wool mop. I went and shot 20 rounds. Came back and used valve grinding compound from Discount Auto Parts (Permatex brand, grit not listed) on the wool mop. Short stroking the bbl like I was trying to get heavy copper out, working 2-3" at the time and making my way down the bbl. I did this once from one end to the other. Finished it off with more IOSSO, cleaned it, and shot another 20 rounds. Came back and did a 3rd scrub but this time with the VGC on a tight patch. Followed by IOSSO, then I went and shot it again. I followed this process blindly because it's what John told me to do. I've spent enough time with him not to question it anymore when he tells me to do something. I loaded up 15 rounds to do a "post treating" load development. I was back in my accuracy node with the same MV with 1.5gr less powder than my original load when the bbl was new. After the bbl was broken in, it went from 71.3gr to 71.0. I'm now at 69.8gr and the gun just shoots! I haven't shot it in a match since it was treated but I did win the first 1k match I shot it in before treatment. I have no doubts about the bbl performing. I'm keeping a round count so I'll know how it recedes. Since the gun this goes in is a DTA, I can take the bbl out in about 30 seconds.

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My understanding is the process leaves a fish scaling on the inside of the bore. If the bbl has been shot, specifically in the throat area, there may be some burnishing that allows this "film" to grab hold. John told me the more a bbl was shot, the more work you have to do on it to get it back. My 7WSM was at the brink of being too far gone with 150 rounds down the tube. Joel recommends no more than 50 rounds fired from any caliber.

Interesting... 50rds is barely enough to even begin to do any serious load testing, in my opinion. Then again, I don't consider load development complete until I've shot a couple matches start to finish, so my perspective may be a bit skewed :huh:

I've got a new Brux heavy Palma .308 barrel sitting here that I want to start using this year... I was contemplating sending it in for this treatment. Wonder how many rounds of match-grade accuracy a treated .308 Win would be good for ;)

I'm wavering on the edge of buying a 7WSM off a friend who started, but never really got into competitive shooting. It's got 118rds logged on the barrel. Sounds like I might be better off just using this barrel for load development, practice, and familiarization and look at treating the next tube I put on it.

Thanks for the detail on the bore-lapping process you went through.

Monte

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My initial load testing for smaller calibers like the .308 uses 35 rounds. I've a method for finding what I need in that. The .338LM was 2 separate 9 round ladder tests.

I'll be nitro treating ALL of my bbls in the future!

The thought of 15,000 rounds in a .308 tube makes me quite thrilled.

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The thought of 15,000 rounds in a .308 tube makes me quite thrilled.

True... although there is part of me that thinks I might get just a wee bit bored waiting for the darned thing to up and die ;)

I wonder... how well a barrel that is somewhat rough to begin with - like a factory Savage F/TR .308 barrel - would take to this process? I know they look rougher than an old corn cob sometimes:huh:, but they do seem to shoot fair-ta-middlin :rolleyes: I know I sure wish I could have immortalized the barrel I have on there now. Started out jumping B155.5BTs 47 thou to the rifling; now ~3500rds later they're jumping something more like 113 thou and still shooting well enough when I do my part.

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I would be interested in any updates as well a year and a half later as I'm getting ready to have the same treatment done on a 260 barrel.

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