Nitride a barrel?

[65WSM]

I have had fifteen barrels, salt bath nitrided, Some using non toxic salts (Melonited) and arsenic salts, both new barrels and used. I have worn out seven 17 Reminton, 6.5 WSM, 6.5-284 Win .22-250 AI, .204 Ruger, .20 PPC. Since I use HBN coated bullets, I can take advantage of the speed from reduction of the bore drag. Obviously, I am a proponent of the process. I have a .22 BR and .20 PPC barrel I am waiting on processing now.

I have a couple of newer reloading dies that are nitrided. One is a RCBS .204 Ruger "small base" sizer I use for my Shilen AR barrel and the other is a Whidden .20 BR custom. They are amazing. Much smoother to operate.

 

[HRM Johnny]

I just had my first rifle barrel, bolt and action nitride treated. I have less than 30 rounds down the barrel, but it does seem to shoot fast. Reloading manuals show about 150 fps slower than what I am getting. Time will tell how it works out. Look forward to hearing other other people's experiences.

Please keep us updated!

 

[HRM Johnny]

FYI
I found these previous Posts.

Is it possible to damage or affect the accuracy of a barrel by black nitriding it?

milo-2 It's not that I have any disdain for Cerakoting....it's just that I prefer the traditional simple black matte or blued finish. One thing I've read about the Cerakoting process is that it does add thickness and can cause stickiness and binding; another reason to avoid it in my mind. And...

www.longrangehunting.com

Barrel and Action Nitride Coating | Long Range Hunting Forum

Is it possible to damage or affect the accuracy of a barrel by black nitriding it?

I am in the process of planning a new rifle build and would like to end up with something other than a shiny SS finish. I don't care for the Ceracoat....just want to end up with a nice black matte/satin finish if possible and the Black Nitriding process appears to be that for which I am...

www.longrangehunting.com

Thanks Len! I remember reading that a while back. I searched for it a few times, but was never able to find it.

 

[HRM Johnny]

The one with 10741 rounds is just one data point, I do not know if that would be the norm or the aberration. We have not pulled any of the other treated ones. There is more coming up about to be pulled at close 6K rounds that I also mentioned.

We have barrels out there right now that have as much as 6k rounds through them that are still very competitive at 600 yards.

One of mine with over 2K rounds still hammers 600 yards. Here is a screen shot of the last targets shot at 600. The eTarget was a Shotmarker. I did not shoot this, I loaned my rifle and load to a friend to shoot in the match. This is from a 20 inch service rifle with a 4.5X March scope. My buddy out X'ed the 6mm any rifle any sight winner in the agg, 63 vs 59.

Another data point worth mentioning, one of our top shooters who won the Presidents Hundred a couple of years had one of his barrels nitrided. This one he established the precision and velocity before the treatment. Post treatment, the velocity from the same load went up almost 80 FPS. He had to back down the powder charge to get it back to the node. How did the treatment affect precision? Hard to tell, he just set a range record at the Talladega 600 match last month with the barrel. The match was held at the CMP range in Alabama.

My take right now, the longevity appears to be better, how much more? The sample is still too small to have high enough confidence level to make a statement. In a couple more years we will have over 50K rounds shot through all the treated barrels.

View attachment 166337

Did you get to 50,000 rounds? If so, what were the results? Also, thanks for sharing your experience/knowledge.

 

[Taj]

Ultimately, I think it's not worth the expense, inconvenience, and possibility of receiving a faulty treatment process, having nitride treated a few barrels. It can change headspace, and it eliminates any future rechambering on the hardened nitrided barrel.

I had one nitride barrel firecrack the bore terribly after a couple hundred rounds fired. A wasted Krieger barrel.

I was once a proponent. No more nitrided barrels for me. Just adds another process that can be done improperly, all for little potential benefit.

I was an LE field rep/ armorer instructor for a big pistol maker when they first came into the US. They used Tenifer as a finish which is a brand name for a salt bath quench nitrate finish. Never had an issue with early 9mm pistols however when the .40 S&W hit the streets issues started popping up in the form of barrel catastrophic failures. .40 pressures and of course the bore/groove diameter in the same parent barrel didn't help matters. They would never publicly admit to a problem and blamed it on ammo makers. In fact, they were one of the major reason SAAMI lowered the max chamber pressure of the .40S&W. . (from 36k to 32k if I remember right) No one else was having the same issue. A Sgt that ran the range at a very large PD in Texas was also head of IALEFI (International Law Enforcement Firearms Instructors Assoc) had several failures (with a couple of minor injuries) and sent pistols off to HG White labs for eval. It was discovered that the Tenifer process was creating microscopic "checking" in the finish and metal surface. The checking ( nitrogen embrittlement) would continue to migrate through the barrel metal until at some point in that pistols life, it would no longer proof like it did when new. A combo of this and any ammo anomaly was a recipe for a failure. The pistol maker did no additional heat treat on their barrels other than the Tenifer treatment. S&W heat treated their barrels which limited the nitrogen embrittlement migration. They were using Melonite, which is the same basic process. My point is, it's a great, very tough finish but has some draw backs if not done correctly and I believe that the parent product it is applied to, can greatly affect the performance results.

 

[bamban]

Did you get to 50,000 rounds? If so, what were the results? Also, thanks for sharing your experience/knowledge.

In a couple more years, we will have that many rounds through all the years. I will ask our equipment manager what is his best count to date. My guess we might be over my stated count. Reason, on our training week every year at Perry we burn 10k plus rounds in a week of training between 12 to 18 kids. But, almost half of the rounds are fired in rattle battle, where each 6 person team burns 384 rounds per pass. Rattle battle is really hard on the barrels. At 6 and 5, shooters dump as many rounds as they could in 50 minutes. Load count is typically 30 rounds.

The varying rounds counts before we pull out is still not known why other barrels last longer than others. So, we made a conscious decision to pull out barrels after 5K. Typical button barrels, the collective opinion across service rifle community X count at 6 diminishes between 2500 and 3K.

 

[bamban]

I was an LE field rep/ armorer instructor for a big pistol maker when they first came into the US. They used Tenifer as a finish which is a brand name for a salt bath quench nitrate finish. Never had an issue with early 9mm pistols however when the .40 S&W hit the streets issues started popping up in the form of barrel catastrophic failures. .40 pressures and of course the bore/groove diameter in the same parent barrel didn't help matters. They would never publicly admit to a problem and blamed it on ammo makers. In fact, they were one of the major reason SAAMI lowered the max chamber pressure of the .40S&W. . (from 36k to 32k if I remember right) No one else was having the same issue. A Sgt that ran the range at a very large PD in Texas was also head of IALEFI (International Law Enforcement Firearms Instructors Assoc) had several failures (with a couple of minor injuries) and sent pistols off to HG White labs for eval. It was discovered that the Tenifer process was creating microscopic "checking" in the finish and metal surface. The checking ( nitrogen embrittlement) would continue to migrate through the barrel metal until at some point in that pistols life, it would no longer proof like it did when new. A combo of this and any ammo anomaly was a recipe for a failure. The pistol maker did no additional heat treat on their barrels other than the Tenifer treatment. S&W heat treated their barrels which limited the nitrogen embrittlement migration. They were using Melonite, which is the same basic process. My point is, it's a great, very tough finish but has some draw backs if not done correctly and I believe that the parent product it is applied to, can greatly affect the performance results.

Thank you for sharing. Early on I cut the crown at straight 90. Just burnish the sharp edge of the crown. We experienced early degradation of precision. What I found the sharp 90 crown was so brittle that showed crown damage. I re-crowned the suspect barrel with a chamfer. Precision was restored.

Back in 2009 I sent out all metal parts for my M1A hunting and defense rifle, except the receiver. The place do not have FFL, still don't. Over 200 rounds in testing rifle had failure to fire. Extracted the round, chambered another, same problem. Found out the tip of the firing just sheared off. Meloniting went through and through making the tip so brittle.

Replaced firing pin with non treated and fired a few more hundreds, no issue. Rifle is truck gun when I hunted by the TexMex border, thus the reason I wanted to make sure it went bang.

 

[Taj]

Thank you for sharing. Early on I cut the crown at straight 90. Just burnish the sharp edge of the crown. We experienced early degradation of precision. What I found the sharp 90 crown was so brittle that showed crown damage. I re-crowned the suspect barrel with a chamfer. Precision was restored.

Back in 2009 I sent out all metal parts for my M1A hunting and defense rifle, except the receiver. The place do not have FFL, still don't. Over 200 rounds in testing rifle had failure to fire. Extracted the round, chambered another, same problem. Found out the tip of the firing just sheared off. Meloniting went through and through making the tip so brittle.

Replaced firing pin with non treated and fired a few more hundreds, no issue. Rifle is truck gun when I hunted by the TexMex border, thus the reason I wanted to make sure it went bang.

Bamban,

Yeah, looks like you found the issue the hard way. Small parts and sharp edges is generally where issues will show up first. I think parts that have inherited a lot of machining stress during the manufacturing process do not tolerate the process very well unless they are stress relieved before being nitrated. I have seen similar issues on both button and hammer forged barrels that aren't properly stress relieved. I have also seen failures with hardchromed bores also due to embrittlement. Robby Barkman (Robar) used to tell me that he felt that hardchrome and Tenifer/ Melonite, had the potential to be catastrophic unless done correctly. Robby is a smart SOB and cut his teeth in the aerospace coatings industry and knew of which he spoke.

 

[Bob Wright]

In the aerospace world, we used vacuum furnace nitride (nitrogen gas) on a variety of steels for wear purposes such as gear shaft journals and helical rotors. It was great for wear but due to its extremely high hardness on the surface there would be instances of damage during manufacturing or in service. We selectively treated high wear surfaces like bearing journal's or rotors using copper plate to mask. It would build on surfaces causing changes to dimensions so those required careful grinding to restore dimensions.
It's high hardness and higher brittleness was always a trade off over carburizing and toughness. I'm not surprised there are failures where sharp corners or fillet radius situations exist. Rifling would be a concern in my eyes. Any other sharp areas after nitriding are stress concentrations where cracks like to form and migrate.
There obviously is barrel applications here in this thread that work and some that don't.
YMMV.

 

[Justice1327]

I just got my 6/6.5PRC barrel from TS Customs. I plan to shoot it ~100rds, send off to 300Below and then to H&M for nitride. Hopefully it will last longer than my previous one

 

[IridiumRed]

Man, i wish barrel nitriding didnt seem like such a gamble, or at least a gamble w such bad odds (in my case i only care about extending useful life of highly accurate barrels, nitriding obviously has great proven benefits in terms of corrosion resistance, finish wear resistance etc).

I think about once a year i look into this subject, and every time i end up deciding not to do it. I guess i keep hoping to find a different answer... or maybe i keep hoping to find that someone has made some breakthrough on the process / procedure that suddenly just seems to work everytime (or at least worked a very high percentage... like... 98% of time is great, only 2% seemed to fall out, i could live with odds like that).

One thing i think might make the difference is bamban's soaking the barrels for a week in water. Seems like hes having repeatable success w these barrels, and i dont hear of anyone else doing the water soaking. I could see the -potential- for it to soak out some of the chemicals involved (though im no chemist / metallurgist).

One thing ive thought about a lot is that they say that you need to have a barrel broken in before nitriding it, because whatever sharp edges are there before processing, are going to be there a long time, be tough on bullets going down essentially new (rough) surface every shot. BUT... when jacketed bullets are fired, it leaves copper behind*, we all know that, but even w a new barrel, and only a few shots fired, its really hard to get ALL the copper out.

A tiny amount of copper can remain behind, maybe stuck in the pores of the steel, or microscopic cracks, grooves, whatever, and in those tiny spots the nitriding doesnt prpoperly work, fails quickly. Creates the rough throat / high pressure / low speed situation so many seem to find w nitrided barrels.

*along w some other fouling, but ive -heard- that its the copper fouling thats the worst in regards to nitriding issues.

I do wonder what it is that allows bamban to seemingly have success whereas its so hit and miss w everyone else (with too many misses for my comfort level)?? If it was one guy with a couple barrels, i could understand it more (sample size so small its not a sample, its just anecdotes at that point), but hes done enough to start being noticeable statistically.

Stuff that i think works in bambans favor (for why nitriding works well for him) is partly how its used - some of that rapid fire shooting, i know thats where youll see a big difference in barrel life between a nitrided (or chrome) barrel versus a regular non treated barrel. Thats true with lower precision rifles (ARs and similar where people are looking for / happy w 2 moa or worse performance... or getting into machinegun territory... treated barrels seem to last much better there)

One thing ive thought about many times is using a different process to break in a barrel before nitriding. I wouldnt want to use lead lap, because barrel is alrwady chambered, youd have a big leap between back of barrel and the throat, be hard to keep everything aligned, and a lead lap is more aggressive then id wsnt anyways. Ive thought about just using a patch rolled around a jag, with one of the JB compounds or similar non embedding lap on it.

Not trying to measurably change bore at all, just want to smooth the rough jagged edges post machining. That would have the benefit of not leaving any copper behind, almost nothing left behind at all. And the fact that whatever is there for contamination was put there by hand power (vs getting slammed into the surface w 60k of pressure behind it) should make it much easer to clean up / remove all traces.

i have a former match rifle that came yo me w one barrel that was in terrible shape. Not sure whatwas done to it, i think maybe a lot of moly coated bullets w not much cleaning done for a very long time / many many shots. It had heavy layers of fouling the whole length of bore, copper and carbon (and maybe moly too), and lots of scratching too. I used JB and similar and basically hand lapped it away (w cloth patches, not a lead lap). Tried to taper the result too, way more aggressive at throat, way less at muzzle (which fit in w the pattern of fouling too). I just had nothing to lose, barrel was pretty useless in terms of accuracy. Any kind of "standard" cleaning really didnt touch what was there. Worked great btw, rifle became great shooter (only thing holding it back was the "nut behind the butt"). Got some more useful life out of barrel (another 500 rounds of 600, 1000 yard shooting), but its pretty much done now, time for new one (still shoots pretty decent at 600 but falls apart at 1000).

Ive also thought about shooting break in shots w something lower pressure and wo jacketed bullet. A 20 or 30k paper patched pullet (patched in such a way that the bullet metal doesnt touch rifling), might be interesting, paper can be pretty good at smoothing steel, taking off rough edges. Should leave behind no metal fouling from bullet too.

Anyways, enough rambling, just wanted to share a few thoughts... barrel nitriding for a precision rifle, man i WANT it to work, it just seems to always be just a bit too much chance of having it not work ... keep trying to find way to close that gap.