Nitride salts or fouling

**tomme boy** · 06-22-22, 23:30

Just about every barrel I have had that was nitride coated has had a orangish brown fouling when wiping out a brand new barrel. This one is no different.

Here is the thing. I have done 5 soakings with the older cans of gunslick foam cleaner. I still had what looks like copper fouling. Sort of. The color is off for what I normally see with copper.

So, I broke out the Sweets 7.62 cleaner. I soaked the bore for 15 minutes and cleaned it out. I did this twice. And whatever the fouling is, it is not coming out. I then got out a brand new brush and some Amsoil bore cleaner. I scrubbed the barrel for about 25 strokes and then ran patches till it was almost spotless on the patches.

The fouling is still there and has not changed at all. The foam always leaves a blue slime on the rag I set the barrels muzzle down onto. I use that as a indicator of how much copper is in the barrel. And nothing showed on the patches with Sweets either.

Would this be some kind of hard oxide that formed during the nitride treatment?

**MegademiC** · 06-23-22, 07:33

Alkaline cyanides are white, and I assume thats what is used. I dont know what the possibility of ferricyanides being formed is, but they are reddish/brown.

**constructor** · 06-23-22, 09:59

Originally Posted by tomme boy

Just about every barrel I have had that was nitride coated has had a orangish brown fouling when wiping out a brand new barrel. This one is no different.

Here is the thing. I have done 5 soakings with the older cans of gunslick foam cleaner. I still had what looks like copper fouling. Sort of. The color is off for what I normally see with copper.

So, I broke out the Sweets 7.62 cleaner. I soaked the bore for 15 minutes and cleaned it out. I did this twice. And whatever the fouling is, it is not coming out. I then got out a brand new brush and some Amsoil bore cleaner. I scrubbed the barrel for about 25 strokes and then ran patches till it was almost spotless on the patches.

The fouling is still there and has not changed at all. The foam always leaves a blue slime on the rag I set the barrels muzzle down onto. I use that as a indicator of how much copper is in the barrel. And nothing showed on the patches with Sweets either.

Would this be some kind of hard oxide that formed during the nitride treatment?

I make/produce Melonite treated AR barrels probably 150,000 in the last 10 years.
What you see in the new barrels most of the time is residue mixed with oil or the company's rinse left in the barrel from the Melonite process, it is not rust...most of the time. IF you remove the black with strong chemicals the bore will rust, it will still be hard(60 rockwell) but it will rust unless you keep the bore coated with oil. I would be very careful with ammonia, if left too long it can pit the bore and it will be splotchy rough spots.

This is the exception and problem- Some Melonite/Nitride companies clean the barrels better than others. After removing from the vat the barrels should be dipped in a rinse immediately, if they are allowed to cool while having the salts they will form a thin layer of baked on salts. Bodycote in Wis is probably the worst for rinsing barrels, I use to spend 30 minutes on each barrel to get the dried residue out. H&M does a pretty good job of rinsing but some batches don't get rinsed fast enough and they don't give a damn if you like it or not. I've never received a single barrel with dried residue from Parker Trutec Arkansas. From my little experience Burlington in Ca. also did a good job.

IF, the salts are left in the bore without rinsing by the company or cleaned as soon as you get the barrel they can cause rust/corrosion and pit the barrels over time.
Yes I know WD40 was made as to displace water. It is mostly alcohol(similar) and as the alcohol evaporates it leaves a thin layer of oil. It works very well to clean Melonite treated barrels without being a very strong chemical that can harm the bore. If a patch alone does not remove the flat spots you see in the bore use a brush wrapped with a patch and soaked in WD. It is safer and does not remove the black.
ETA- Just to be clear, you are removing the black. What you see is places where you have removed all of the black and other places where some is still showing/thin.

**gaijin** · 06-23-22, 11:58

Good info.

I've used H&M on three projects and was satisfied.

**ABNAK** · 06-23-22, 17:51

Sorry, this just adds to my hesitation to buy a nitrided (Melonited) barrel. I know chrome lining has it's flaws at times but to me this is just another nail in the nitride coffin.

YMMV and no disrespect intended to anyone.

**ABNAK** · 06-23-22, 17:54

Originally Posted by constructor

I make/produce Melonite treated AR barrels probably 150,000 in the last 10 years.
What you see in the new barrels most of the time is residue mixed with oil or the company's rinse left in the barrel from the Melonite process, it is not rust...most of the time. IF you remove the black with strong chemicals the bore will rust, it will still be hard(60 rockwell) but it will rust unless you keep the bore coated with oil. I would be very careful with ammonia, if left too long it can pit the bore and it will be splotchy rough spots.

This is the exception and problem- Some Melonite/Nitride companies clean the barrels better than others. After removing from the vat the barrels should be dipped in a rinse immediately, if they are allowed to cool while having the salts they will form a thin layer of baked on salts. Bodycote in Wis is probably the worst for rinsing barrels, I use to spend 30 minutes on each barrel to get the dried residue out. H&M does a pretty good job of rinsing but some batches don't get rinsed fast enough and they don't give a damn if you like it or not. I've never received a single barrel with dried residue from Parker Trutec Arkansas. From my little experience Burlington in Ca. also did a good job.

IF, the salts are left in the bore without rinsing by the company or cleaned as soon as you get the barrel they can cause rust/corrosion and pit the barrels over time.
Yes I know WD40 was made as to displace water. It is mostly alcohol(similar) and as the alcohol evaporates it leaves a thin layer of oil. It works very well to clean Melonite treated barrels without being a very strong chemical that can harm the bore. If a patch alone does not remove the flat spots you see in the bore use a brush wrapped with a patch and soaked in WD. It is safer and does not remove the black.
ETA- Just to be clear, you are removing the black. What you see is places where you have removed all of the black and other places where some is still showing/thin.

I have a question: I know ammonia-based solvents are not good for chrome lined barrels, especially if left to sit too long. But I was always under the impression that nitride was impervious to the things chrome wasn't, i.e. solvents. It *might* have been the only advantage I would have given to a nitrided barrel but apparently that isn't the case?

**constructor** · 06-23-22, 19:23

Originally Posted by ABNAK

I have a question: I know ammonia-based solvents are not good for chrome lined barrels, especially if left to sit too long. But I was always under the impression that nitride was impervious to the things chrome wasn't, i.e. solvents. It *might* have been the only advantage I would have given to a nitrided barrel but apparently that isn't the case?

Nitride barrels(60-65 rockwell) are as accurate as stainless (28-30 rockwell) and last much longer, the exterior of the Nitride barrel is also much more corrosion resistant than parkerized(manganese phosphate) chromelined barrels.
If you don't use the wrong solvents or do the wrong things Melonite is better than chrome lined IMO. In 2009 I had 200 barrels made, 223 Wylde Polygonal 8 twist, testing before sending off for chrome they were shooting 3/4" easy enough. After sending them off to be chromelined they shot more like 2.5" with the same ammo. From what I can see the only thing a chrome-lined barrel does better than a Melonite treated barrel is handle heat under full auto fire.