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Blownmotor
12-14-2011, 10:21 PM
Does anyone here own a barrel that's melonite coated? Tried searching here and google but came up with a bunch of opinions and arguments. I like the idea of it making the surface harder and slicker whlie retaining the barrel's inherent accuracy but it dosn't say anything about corrosion protection. Also no one has any idea of the longevity of the coating itself. I see S&W using it on their M&P Sport and Bushmaster using it on the ACR. Any Clarified info is appreciated thanks.

shortround1
12-14-2011, 10:23 PM
I think Zombie Tactics has recently been putting his M&P 15 through the paces. You can search for his thread or check out his youtube stuff. He seems to give pretty good, no BS opinions on his stuff.

Edit, here: http://calguns.net/calgunforum/showthread.php?t=490629

zfields
12-14-2011, 10:25 PM
Does anyone here own a barrel that's melonite coated? Tried searching here and google but came up with a bunch of opinions and arguments. I like the idea of it making the surface harder and slicker whlie retaining the barrel's inherent accuracy but it dosn't say anything about corrosion protection. Also no one has any idea of the longevity of the coating itself. I see S&W using it on their M&P Sport and Bushmaster using it on the ACR. Any Clarified info is appreciated thanks.

Melonite is basically the same stuff used on glock/XD slides. Very wear and corrosion resistant.

winxp_man
12-14-2011, 11:45 PM
I just got a Adams Arms piston upper and took off the stock hand guards and installed a Troy hand guard. Well in the process I used a monkey wrench to take off the stock barrel nut because the one that came with the troy rail was to small. Now my wrench slipped a few times and dinged up the delta ring a tad and also the barrel nut, but not one scratch on the barrel which they say is coated with melonite.

chicoredneck
12-15-2011, 4:23 AM
Here is a chart showing the corrosion resistance of melonite treated steel compared to hard chrome and nickel plating.
http://www.ar15performance.com/

C4iGrant
12-15-2011, 4:55 AM
Does anyone here own a barrel that's melonite coated? Tried searching here and google but came up with a bunch of opinions and arguments. I like the idea of it making the surface harder and slicker whlie retaining the barrel's inherent accuracy but it dosn't say anything about corrosion protection. Also no one has any idea of the longevity of the coating itself. I see S&W using it on their M&P Sport and Bushmaster using it on the ACR. Any Clarified info is appreciated thanks.

I had some BCM 410 SS barrels done and will be testing.

The company that is most known for doing this, is right up the road for me. I have also had a BCG done, but have not had a chance to test it yet.



C4

chicoredneck
12-15-2011, 5:17 AM
I had some BCM 410 SS barrels done and will be testing.

The company that is most known for doing this, is right up the road for me. I have also had a BCG done, but have not had a chance to test it yet.



C4

Let us know how it goes. I have not been able to find a purely unbiased source of information. I am also curious if the treatment is different on ss that it is with cm.

I had an XD pistol that was melonite treated. It held up very well, but it did not get very much abuse. My glock (slightly different treatment than melonite) has been tortured and its finish is still almost like no. No rust or corrosion. You can literally wash them in the dishwasher. Pretty cool.

Richard Erichsen
12-15-2011, 11:05 AM
Does anyone here own a barrel that's melonite coated? Tried searching here and google but came up with a bunch of opinions and arguments. I like the idea of it making the surface harder and slicker whlie retaining the barrel's inherent accuracy but it dosn't say anything about corrosion protection. Also no one has any idea of the longevity of the coating itself. I see S&W using it on their M&P Sport and Bushmaster using it on the ACR. Any Clarified info is appreciated thanks.

Yes (by a different trade name) but it's not a "coating" it's a thermo-chemical process akin to a modified case hardening of the steel part with a hard outside case (the compound layer) an area with a lesser amount of carbon/nitrogen enrichment between the compound and base layers (the diffusion layer) and finally the base metal, which remains unaffected.

The process is being used in place of hard chrome and for the same reasons, including corrosion, wear and thermal enhancement. There are ASTM salt spray tests used on these processes and minor tweaks can be made to the process to enhance salt spray performance at the expense of some amount of wear resistance.

Many of the European firearms manufacturers have been using any of several process names for seveveral years instead of chrome plating, including in environments where corrosion can be a problem. Two main types of nitrocarburizing are used (there are about six total): Gas nitriding and molten salt bath nitriding. Of the two, processes, salt bath nitriding methods tend to achieve a deeper case.

Melonite, Isonite, Tufftride (and several other trade names) are basically the same process (QP and QPQ) using molten salts to permeate the base metal with nitrogen and carbon. The final result after processing is a hardness of 60-62 HRC for chrome-moly steels like AISI 41xx and a hardness of 70-72 HRC for steels like 416/417. A typical barrel before treatment is in the 32 HRC/38 HRC range (hard chrome is of course quite hard with hardness in the 70 HRC range).

Unlike chrome, which can fracture, chip or peel off, the nitrocarburizing process applies to the base metal and has a depth (including the diffusion layer) much thicker than the chrome plating and while it may chip if abused, it cannot peel off and it would be difficult for a microfracture to propagate before it encountered the diffusion layer or base.

My first encounter with a nitrocarburized barrel was a Galil ARM. I didn't know what the process was and assumed it was inferior, US milspecs called for a chromed lined barrel in the M16A1 through the latest M4, AK's overwhelmingly had chrome lined bores, chambers and gas pistons and nothing in my experience seemed like it could easily replace a well applied chrome plate. My thought at the time was this might have been intended as a cost cutting measure to approximate some aspects of chrome. Years later, not having really paid much attention to it, a friend bought a SIG 556 and almost didn't buy it because it's barrel was not chrome lined. Thinking there had to be something to this, I did some research and found it was superior in almost every respect and that in many applications (including hydraulic systems and marine applications) chrome plating was being replaced.

When I had a clutch of unlined barrels, unfinished and in the white that I had planned to use for some HK/CETME and there AK builds, I decided to give it a try. The barrels that were treated came back with a lamp black exterior and a shiny interior - the entire barrel had been treated with equivalent or superior hardness, abrasion and corrosion resistance to chrome along the entire barrel.

Barrel life estimates from some of the production houses that treat barrels for major manufacturers have suggested 2.5-5 times improvements in useful life based on specific tests performed against ASTM such as salt spray and thermal testing. At this point there is a large amount of live field testing with barrels treated with these process in firearms made by the likes of SIG, HK, Glock, Steyr, and a host of others.

There is plenty of information available from the production houses that perform these treatments and most have technical support lines (the folks sales will forward you to if you call with these questions) that can help you out.

http://coalcreekarmory.com/custom_finishing.html
http://www.burlingtoneng.com/melonite.html

I have had my barrels treated in Isonite QPQ (a different trade name for the same process). Price can be a problem for an end user if its not already done when you buy it. There is a thread on the topic if you want to send a well cleaned barrel to try it out come Spring when the next batch goes out. You can contact Roccobro for details.

R

C4iGrant
12-15-2011, 11:09 AM
Let us know how it goes. I have not been able to find a purely unbiased source of information. I am also curious if the treatment is different on ss that it is with cm.

I had an XD pistol that was melonite treated. It held up very well, but it did not get very much abuse. My glock (slightly different treatment than melonite) has been tortured and its finish is still almost like no. No rust or corrosion. You can literally wash them in the dishwasher. Pretty cool.

Will do.


C4

zfields
12-15-2011, 11:11 AM
Let us know how it goes. I have not been able to find a purely unbiased source of information. I am also curious if the treatment is different on ss that it is with cm.

I had an XD pistol that was melonite treated. It held up very well, but it did not get very much abuse. My glock (slightly different treatment than melonite) has been tortured and its finish is still almost like no. No rust or corrosion. You can literally wash them in the dishwasher. Pretty cool.

Ill stick with the ultrasonic.


The girl would kill me if she found guns in the dishwasher :oji:
She already gets mad when I use the oven to mold kydex.

ZombieTactics
12-15-2011, 11:34 AM
I had some BCM 410 SS barrels done and will be testing.

The company that is most known for doing this, is right up the road for me. I have also had a BCG done, but have not had a chance to test it yet.
...

I'm very much looking forward to your test results. My understanding is that 410SS probably isn't the best choice for salt-bath nitride processing, but it will be a fascinating data point.

My personal experience has been that a Melonite treated barrel is quite a bit easier to clean. It seems that the "ick" just doesn't adhere to the surface as much. That has to be a good sign of something. The attitude of metallurgists I've spoken to is that Melonite is a no-brainer choice when compared to chrome plating, but then they may have different applications in mind.

beretta929mm
12-15-2011, 11:47 AM
A barrel usually is shot out in two areas, the throat and the muzzle. Throat corrossion is due to heat, and the muzzle is due to improper cleaning techniques. A Melonite treated barrel will help in both.

Richard Erichsen
12-15-2011, 11:57 AM
A barrel usually is shot out in two areas, the throat and the muzzle. Throat corrossion is due to heat, and the muzzle is due to improper cleaning techniques. A Melonite treated barrel will minimize the damage on the muzzle end. But as for excessive heat in the throat area, it is up to the shooter to be less trigger happy.

Even "super alloys" like Inconel which are more an alloy of cobalt than a steel alloy suffer the same issues, just at a slower rate. Melonite supposedly reduces the gas erosion and mechanical abrasion that cuts away at the throat, gas port (if applicable) and muzzle, but I'm unclear on the exact mechanism that reduces the gas erosion (it's basically a gas plasma at these pressures and temperatures and the vaporization temperature of steel that comes into play). I'll make a point to ask that question next time I talk to the shop we've used.

R

RobGR
12-15-2011, 1:01 PM
Can't remember where I found this info, but sent it to a friend who was interested in the M&P 15 Sport, but I believe it was on AR15.com that they were discussing it and someone had found info from a military test.

"Chrome lined barrels lasted an average of 38,000+ rounds. Nitrocarburized (Melonite) barrels lasted an average of 28,000+ rounds. Untreated barrels lasted an average of 6,000+."

EDIT: It was from THR http://www.thehighroad.org/showthread.php?t=597559

grant22
12-15-2011, 1:19 PM
I just got a Adams Arms piston upper and took off the stock hand guards and installed a Troy hand guard. Well in the process I used a monkey wrench to take off the stock barrel nut because the one that came with the troy rail was to small. Now my wrench slipped a few times and dinged up the delta ring a tad and also the barrel nut, but not one scratch on the barrel which they say is coated with melonite.

I thought the bore was coated in melonite, not the exterior.

nani
12-15-2011, 1:32 PM
That post also clarifies that the info was from a 1967 Army study: http://www.dtic.mil/cgi-bin/GetTRDoc?AD=AD822736&Location=U2&doc=GetTRDoc.pdf

Can't remember where I found this info, but sent it to a friend who was interested in the M&P 15 Sport, but I believe it was on AR15.com that they were discussing it and someone had found info from a military test.

"Chrome lined barrels lasted an average of 38,000+ rounds. Nitrocarburized (Melonite) barrels lasted an average of 28,000+ rounds. Untreated barrels lasted an average of 6,000+."

EDIT: It was from THR http://www.thehighroad.org/showthread.php?t=597559

Nathan Krynn
12-15-2011, 1:47 PM
I am not an expert on the subject but 2 years ago we had 10 barrels melonited as samples.

I have shot gosh knows how many rounds through them.

It is not a surface treatment so its not coated at all but the process changes the molecular structure of the metal and the "black" goes all the way through so you should never be able to scratch them. It does change the rockwell so it lasts much longer, much much longer. However you I was told by the rep not to have the extension on there as since it changed the rockwell it might mess up the extension.

The rep also said the best thing was to have a barrel that was lapped to remove all the burs. This is due to it will make those burs much harder (like the barrel) and they won't break off like normally after the first whatever amount of rounds. I did experience this. Since we sent 10 barrels they were all different. One was a barrel that was not match grade or anything and once done we gave it to an engineer that works with us. He is a good shot and said the barrel was only 3 moa or so. Then a year later after a few thousands of rounds the groups were shrinking and now it was like a 1.5 moa or less barrel. We were perplexed by this until we remembered about being warned if there were burs in the barrel they will take longer to break off.

One barrel was a Bison Armory 6.8 spc II and his barrels rock normally. Well it still does and has never been a problem.

It is so different then chrome lining but it is natural to compare but they really are different. The other thing to consider is the good old chrome and phosphate can't really be done in a SS barrel and this can.

So long story short I like the treatment and would use it on my personal guns.

Blownmotor
12-15-2011, 2:45 PM
Thank you guys for all the information and clarifying any misconcepetions.

chicoredneck
12-15-2011, 2:54 PM
Yea, good input.

Richard Erichsen
12-15-2011, 3:36 PM
I thought the bore was coated in melonite, not the exterior.

The whole barrel goes into the molten salt, so the entire barrel is treated, not just the bore.

R

Richard Erichsen
12-15-2011, 3:39 PM
I am not an expert on the subject but 2 years ago we had 10 barrels melonited as samples.

I have shot gosh knows how many rounds through them.

It is not a surface treatment so its not coated at all but the process changes the molecular structure of the metal and the "black" goes all the way through so you should never be able to scratch them. It does change the rockwell so it lasts much longer, much much longer. However you I was told by the rep not to have the extension on there as since it changed the rockwell it might mess up the extension.

The rep also said the best thing was to have a barrel that was lapped to remove all the burs. This is due to it will make those burs much harder (like the barrel) and they won't break off like normally after the first whatever amount of rounds. I did experience this. Since we sent 10 barrels they were all different. One was a barrel that was not match grade or anything and once done we gave it to an engineer that works with us. He is a good shot and said the barrel was only 3 moa or so. Then a year later after a few thousands of rounds the groups were shrinking and now it was like a 1.5 moa or less barrel. We were perplexed by this until we remembered about being warned if there were burs in the barrel they will take longer to break off.

One barrel was a Bison Armory 6.8 spc II and his barrels rock normally. Well it still does and has never been a problem.

It is so different then chrome lining but it is natural to compare but they really are different. The other thing to consider is the good old chrome and phosphate can't really be done in a SS barrel and this can.

So long story short I like the treatment and would use it on my personal guns.

The pentultimate in abrasion and corrosion resistance is a stainless barrel that is QP treated. The surface hardness will be as hard as hard chrome and the case much thicker than is practical for a chrome plating to be, without any of the disadvantages. You can also apply QPQ over a chrome lined chrome-moly barrel and the chrome will absorb the nitrogen and carbon as well. The bore will darken from this treatment, but it actually enhances it's performance. In all cases, outside/inside are treated simultaneously, not just the bore.

R

MrPlink
12-15-2011, 3:55 PM
great info here guys

Socal Armament
12-15-2011, 6:03 PM
If you go to Riflegears website they have Adams Arms melonite barrels, $188 each. For me its a no brainer, its the same price as most chrome lined barrels and I think the melonite finish on the exterior is better than a parkerized finish which scratches easily.

ZombieTactics
12-15-2011, 6:19 PM
... "Chrome lined barrels lasted an average of 38,000+ rounds. Nitrocarburized (Melonite) barrels lasted an average of 28,000+ rounds. Untreated barrels lasted an average of 6,000+."

EDIT: It was from THR http://www.thehighroad.org/showthread.php?t=597559

It should be noted that salt-bath nitride processes have improved considerably since the 1960s. I can think of no cases where chrome-plating would result in a more durable barrel than a properly treated Melonite (or similarly processed) barrel.

Richard Erichsen
12-15-2011, 6:40 PM
It should be noted that salt-bath nitride processes have improved considerably since the 1960s. I can think of no cases where chrome-plating would result in a more durable barrel than a properly treated Melonite (or similarly processed) barrel.

By my calendar, US Army evaluations were between 43 and 47 years ago. Steels have improved, processes and QC have been enhanced and both consistency and performance have been improved.

I'd like to see the testing they performed to calculate wearing out a barrel given that the majority of the firearm components won't last 40K rounds. At current ammunition prices, that would be quite a test, either to test chrome lined barrels to the point of failure, or a Melonite QPQ barrel.

R

dieselpower
12-15-2011, 6:50 PM
We talked about this last year. I was a supporter and had just built a rifle for a Buddy with a CMMG WASP upper. All the cool guys said it was "lower" end gear, For hobbyist not Professionals... LOL

I believe I posted several articles on the subject, but of course it all fell on deaf ears when the "professionals" said it was crap...

FatalKitty
12-15-2011, 7:07 PM
We talked about this last year. I was a supporter and had just built a rifle for a Buddy with a CMMG WASP upper. All the cool guys said it was "lower" end gear, For hobbyist not Professionals... LOL

I believe I posted several articles on the subject, but of course it all fell on deaf ears when the "professionals" said it was crap...

I remember that! i think most of those people went back to M4carbine or something... this forum is much cooler now

Blownmotor
12-15-2011, 7:21 PM
After a lot of reading, how do you know which melonite process did the barrel go through? I read there are 3 types Q, QP, and QPQ.

Richard Erichsen
12-16-2011, 10:13 AM
After a lot of reading, how do you know which melonite process did the barrel go through? I read there are 3 types Q, QP, and QPQ.

From the link I posted above sourced from the vendor that does this sort of work, it's all still "Melonite" (Isonite, Tufftride, Tennifer, etc.). The process steps performed are chosen to achieve a particular end result in the steel. Stainless usually get QP (there was an exception for a specific alloy I no longer recall, not common), while carbon steel and chrome-moly get either Q or QPQ. The outside of the barrels will be Q, which is why they are a deep lamp black.

Melonite Processing: Melonite Q

Improved Wear Resistance
Improved Running Properties
Increased Fatigue and Rolling Fatigue Strengths
Heat Resistance
Black Color

Melonite Processing: Melonite QP

lncludes the properties of Melonite Q
Lower coefficient of Friction
Decreased surface roughness

Melonite Processing: Melonite QPQ

lncludes the properties of Melonite Q and QP
Low Light Reflection
Further Decreased Coefficient of Friction
Enhanced Corrosion Resistance (Not suitable for stainless)

There are entirely different processes that don't use molten sodium that use gas plasma and other methods that I'm just not as familiar with and haven't investigated much beyond the pricing. My understanding from a barrel maker is the differences between a QP/QPQ barrel and a plasma nitrocarburized barrel is case depth and cost. Some of the newer processes are better suited to more exotic alloys. Melonite is still around because of it's good balance of cost for the performance, reasonably easy to do well in a large scale production shop and for ordinance grade steel alloys works very well.

R

dieselpower
12-16-2011, 3:59 PM
From the link I posted above sourced from the vendor that does this sort of work, it's all still "Melonite" (Isonite, Tufftride, Tennifer, etc.). The process steps performed are chosen to achieve a particular end result in the steel. Stainless usually get QP (there was an exception for a specific alloy I no longer recall, not common), while carbon steel and chrome-moly get either Q or QPQ. The outside of the barrels will be Q, which is why they are a deep lamp black.

Melonite Processing: Melonite Q

Improved Wear Resistance
Improved Running Properties
Increased Fatigue and Rolling Fatigue Strengths
Heat Resistance
Black Color

Melonite Processing: Melonite QP

lncludes the properties of Melonite Q
Lower coefficient of Friction
Decreased surface roughness

Melonite Processing: Melonite QPQ

lncludes the properties of Melonite Q and QP
Low Light Reflection
Further Decreased Coefficient of Friction
Enhanced Corrosion Resistance (Not suitable for stainless)

There are entirely different processes that don't use molten sodium that use gas plasma and other methods that I'm just not as familiar with and haven't investigated much beyond the pricing. My understanding from a barrel maker is the differences between a QP/QPQ barrel and a plasma nitrocarburized barrel is case depth and cost. Some of the newer processes are better suited to more exotic alloys. Melonite is still around because of it's good balance of cost for the performance, reasonably easy to do well in a large scale production shop and for ordinance grade steel alloys works very well.

R

I think CGN has found their "Go to" guy about Melonite treatment.

Thank you for the info.

jingerale
12-16-2011, 4:11 PM
From the link I posted above sourced from the vendor that does this sort of work, it's all still "Melonite" (Isonite, Tufftride, Tennifer, etc.). The process steps performed are chosen to achieve a particular end result in the steel. Stainless usually get QP (there was an exception for a specific alloy I no longer recall, not common), while carbon steel and chrome-moly get either Q or QPQ. The outside of the barrels will be Q, which is why they are a deep lamp black.

Melonite Processing: Melonite Q

Improved Wear Resistance
Improved Running Properties
Increased Fatigue and Rolling Fatigue Strengths
Heat Resistance
Black Color

Melonite Processing: Melonite QP

lncludes the properties of Melonite Q
Lower coefficient of Friction
Decreased surface roughness

Melonite Processing: Melonite QPQ

lncludes the properties of Melonite Q and QP
Low Light Reflection
Further Decreased Coefficient of Friction
Enhanced Corrosion Resistance (Not suitable for stainless)

There are entirely different processes that don't use molten sodium that use gas plasma and other methods that I'm just not as familiar with and haven't investigated much beyond the pricing. My understanding from a barrel maker is the differences between a QP/QPQ barrel and a plasma nitrocarburized barrel is case depth and cost. Some of the newer processes are better suited to more exotic alloys. Melonite is still around because of it's good balance of cost for the performance, reasonably easy to do well in a large scale production shop and for ordinance grade steel alloys works very well.

R

Thanks for the info. Thinking about picking up a CMMG 300 AAC barrel, and this helps.