Rifle barrels that will withstand a barrel burner caliber - 6.5X68S

bruce moulds said:

mostly barrels do not WEAR out. (unless they are not cleaned properly)
they ERODE, caused by heat and flame.
the more powder and pressure in relation to the bore surface area, the more erosion.
bruce.

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Well.... I must shoot a lot more then I realize.

I have burnt out more barrels than I can count.

6CM I get about 1100rds
243 about 1200rds
6XC 1400rds
6.5CM 1900rds
308 5000rds
338LM 1200rds

Multiple barrels on each some way more than other. I will add the if the barrel can no longer hold a solid 3/8moa it comes off. I am not implying I can shoot every group every time that tight. When I shoot groups I see what it's doing and act accordingly.

I forgot to add a 7wsm I only got 1300rds out of that one but it was only 1 barrel so not as solid of information.

Members, I do understand the erosion effect of a burst of heat, powder at high temperatures focused on a small surface in a barrel ...still .I am wondering about the steel that is use when a automatic machine gun is fired at high rate for long periods ..why is this steel not applied in the making of hunting/target rifle barrels today?

What type of steel is used for machine guns?

Butch Lambert said:

A stainless match in 32" would be $207.75+$20 shipping in the CONUS.

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This is a great price on such a barrel if I compare it to the quotations I received from barrel companies.

It seems I got an answer for my own question.. Here is some info about the terms used in this conversation, I was not familiar with..

"Meloniting is a trademarked name for a process known as nitro-carburizing. The process has been around for a very very long time and is by no means new.

Chrome lining is an even older process, that came into play during the days when corrosive ammo was being used. It quickly became a military specification due to the durability that it offered automatic weapons. It remains a mil-spec not because it is better then more modern solutions, but due to the "if it ain't broke, don't fix it" mantra that military contract designers have.

The downside to chrome lining is that the accuracy of the barrel becomes absolutely dependent on the quality of the chrome lining. If the lining wears, flakes, or was not applied smooth to begin with, accuracy will suffer.

Nitro carburizing treats the barrel material itself, it is not a coating. Therefor, the barrel remains just as accurate or inaccurate as it was before the process. This process does not wear out, as it changes the molecular structure of the barrel.

In either process, it is best to make sure the barrel is profiled and cut to your liking before applying. Chrome lined barrels that are cut will chip and flake. Nitro carburized barrels are very tough on tools and are expensive to cut due to this (they are very hard).

The good news is that is is very easy to send a barrel off for meloniting or nitro carburizing. If you purchase a quality cold hammer forged barrel that is not treated or lined, you can melonite it to your liking."

Like @Hogpatrol I have had several barrels melonited. 6.5 CM and a 7WSM. 6.5 was good no problems at all. 7 WSM did not fair as well, not sure it's a speed thing or not.

I will say you must have your barrel cut before you have it melonited. Once it's done you will have a very hard time cutting it.

I'll add to the list another place http://otmtactical.com
I get all my barrels from them, a good bunch of guys.

Inline6 said:

Well.... I must shoot a lot more then I realize.

I have burnt out more barrels than I can count.

6CM I get about 1100rds
243 about 1200rds
6XC 1400rds
6.5CM 1900rds
308 5000rds
338LM 1200rds

Multiple barrels on each some way more than other. I will add the if the barrel can no longer hold a solid 3/8moa it comes off. I am not implying I can shoot every group every time that tight. When I shoot groups I see what it's doing and act accordingly.

I forgot to add a 7wsm I only got 1300rds out of that one but it was only 1 barrel so not as solid of information.

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I think we are on different pages here. I would bet there is very few hunters on here whose rifles shoot 3/8" groups and probably quite a few who couldn't shoot a 3/8" group themselves. Nor should either apply for what we are doing. 1.5" will easily do the job for hunting situations out to 300 plus. Maybe you could send me some of your burnt out barrels. I could probably limp by with the poor accuracy.

Graham Hunter said:

I think we are on different pages here. I would bet there is very few hunters on here whose rifles shoot 3/8" groups and probably quite a few who couldn't shoot a 3/8" group themselves. Nor should either apply for what we are doing. 1.5" will easily do the job for hunting situations out to 300 plus. Maybe you could send me some of your burnt out barrels. I could probably limp by with the poor accuracy.

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I don't have any problems doing that. All I shoot are Accuracy International rifles so the due to the barrel tendon and the fact they are metric threads not sure you could get them to work.

So you have a better perspective, when I shoot a match between travel, ammo, hotels, and match fees. I'm spending 1k+ to shoot that match. I have had a barrel crap out on me on the last 4 stages of the match I went from 3rd to 8th. I view a barrel like Nascar views tires. You can practice on used ones but when it comes time to race you are going to have a good set of tires on your car.

So the barrel I do pull usually end up as practice barrels. My oldest took a little 8 this year with an 6XC barrel that I set back. It was only a 100yard shot on a tripod (which again is different than what I see on the sight).

Members is melonite the only technology to ensure longer barrel life? I recently discussed specifications with a well known barrel manufacturer..he mentioned that from May this year their company is making use of a steel that will ensure a longer barrel life especially when barrel burner calibers are concerned.. What is the different military institutions using to ensure a longer barrel life for their automatic assault rifles??? The newest technology these days????

Well you really need to be honest with yourself. What are your expectations ie 1/4 moa groups or are you okay with 1.25 moa groups. How many rounds a year will you shoot? A lot of people say they shoot a lot when in reality they might only shoot a couple of boxes a year.

If it takes you 5 plus years to shoot 1ks rounds it may not be worth it to you to go through the trouble.

And to answer your question chrome line and their accuracy standards are not the highest.

Gert Odendaal said:

Members is melonite the only technology to ensure longer barrel life? I recently discussed specifications with a well known barrel manufacturer..he mentioned that from May this year their company is making use of a steel that will ensure a longer barrel life especially when barrel burner calibers are concerned.. What is the different military institutions using to ensure a longer barrel life for their automatic assault rifles??? The newest technology these days????

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I will forward an email from an Army Armorer that gave his opinion and the results of his extensive testing of AR barrels.

inline6, I have a friend that chambers many many barrels for Accuracy International.

Butch Lambert said:

I will forward an email from an Army Armorer that gave his opinion and the results of his extensive testing of AR barrels.

inline6, I have a friend that chambers many many barrels for Accuracy International.

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Cool! Good chance I probably know him. I chamber my own, have been for the last 4 years or so.

Butch Lambert said:

I will forward an email from an Army Armorer that gave his opinion and the results of his extensive testing of AR barrels.

inline6, I have a friend that chambers many many barrels for Accuracy International.

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Thank you Butch , it really is much appreciated to have the opportunity to get to know more about new barrel technology..this discussion really is great

OK, here you go:
Hello Butch,
I was the Armorer for the Army Reserve Shooting Team for over a decade so I do have quite a bit of experience with both processes.

As I am sure you know, most G.I. barrels are made from chrome molly steel which is more susceptible to corrosion than stainless steel. Chrome lining is used on G.I. bores both to extend their shooting life and to protect them from corrosion that can be a problem in battlefield conditions where maintenance is sometimes sporadic or insufficient. Chrome lining does a pretty good job of protecting battlefield weapons. One of the objections to chrome lining is that it is thought to decrease accuracy. This seems to be a valid criticism and is backed up by machine rest tests I have conducted of identical barrels (same manufacturer but half chrome lined and half not).

As you are aware most barrel "wear" is in the throat area. So eventually the hot gasses from the burning of the gunpowder will eat thru the chrome lining at the throat. It is rumored that at this point accuracy will plummet but I have not found that to be true. (Or if true, it is overstated or maybe only occurs for that short period when there is both chrome and bare steel in the throat simultaneously - just at the point of initial break thru.) Chrome lined barrels can continue to shoot well for thousands of rounds after the bare barrel steel at the back of the barrel (throat) has been exposed due to erosion of the chrome lining. Another criticism of chrome lining is that it can flake off later in the life of the barrel resulting in poor accuracy. Obviously, this could also cause maintenance problems if the user is depending on the chrome to ward off corrosion and thus is careless in his bore cleaning. If corrosion is allowed to occur pitting will result and that will ruin accuracy for sure.

Barrel pitting was one of the reasons I got involved in Salt Bath Nitriding. I was loosing nearly as many expensive match grade barrels to improper maintenance (causing pitting) as I was to wear out. This was under the relatively benign target shooting conditions. Obviously given the reputation of degraded accuracy, using chrome lining wasn't an option. So for the past couple of years I have been Salt Bath Nitriding all of my match barrels and haven't had a single one exhibit any pitting. During that 2 yr. period shooters have put anywhere from a few hundred rounds to thousands of rounds on said barrels. I don't know how long the coating will persist so at this point I am still evaluating it as a preservative. I don't know what will happen in another year or two when these barrels get more wear on them. Salt Bath Nitriding goes on both inside of the bore and on the outside surface. So, instead of 2 manufacturing steps you have combined them into one. Salt Bath Nitriding doesn't degrade accuracy one iota, unlike chrome lining. This was the first thing that I verified when I began using the process. I broke in a bunch of barrels and then machine rest tested them for group. I recorded and kept the targets, cleaned up the barrels, and sent them to MMi TruTec for the Isonite process. When they came back I reassembled them on the same receivers with the same torque settings, same bolt carrier assemblies, same flash suppressors, etc. Then they were retested with the same ammo lots. NO degradation in accuracy and about a 1% increase in muzzle velocity.

Chrome lined barrels seem to clean up rather easily after a range session. I found the ease of cleaning of Isonite coated barrels to be similar to chrome lined barrels. The Isonite barrels clean up the easiest of any non chrome lined barrels I have ever used. Isonite can be applied to either stainless or chrome molly but the factory needs to know what steel you are sending them because the application process varies a bit. Again, I only have about 2 yr. of cleaning experience with Salt Bath Nitrided barrels. I don't know if the ease of cleaning will continue as the barrels get more rounds on them. Generally speaking, most non coated barrels get harder to clean later in life. Although stainless has a reputation of being corrosion resistant it isn't corrosion proof (I have had plenty of them return pitted) so I coat both my C.M. and my SS barrels. The Isonite on the outside of the stainless barrels cuts reflection down so my shooters like it.

I mentioned flaking of chrome lining inside the bore. Joel Kendrick is my contact at MMi TruTec, the company in Arkansas that does my Salt Bath Nitriding (they call it Isonite). He was mentioning using the Salt Bath Nitriding inside the bore prior to chrome lining it to get a better adhesion. He is currently working with one of the military contractors (maybe F.N., but don't quote me on that) relative to this process. He has given me permission to give out his contact information so I have cc'd him in my reply to you. He can give you the specifics of any testing and evaluation that has been done relative to this process and can give you quotes, etc. should you just be interested in the Isonite by itself as I use it.

One last quick note on chrome lining. Such barrels have the reputation of changing point of impact when heated up. I have found this to be very true. It may be due to the way the different metals (chrome molly and chrome) expand inside the bore. What ever the reason, it does happen and, again, this was verified on a state of the art machine rest. Isonite doesn't exhibit this characteristic.

I am sure you are well aware of some of the things I covered. Lacking specific questions, I just sort of used a shotgun approach which ended up being fairly long. If I left anything unanswered please feel free to get back to me. I have enabled my Spam Blocker to allow your e-mails to come in with out the automated hate responses that Earth Link sends out. I am sure Joel would also be glad to clarify the technical aspects of the Salt Bath Nitriding process. So far I am very pleased with it.

Best of luck!

Butch , thank you for the effort to get this report/feedback from this person, it really is a lot of info in regards to this thread...really great, thank you very much..

Joel Kendrick is originally from North Carolina. He is a past long range shooter of the year. Joel worked for a company that used the Melonite "Isonite" on their wear parts. It intrigued him and he started treating his long range barrels to make them last longer. He did a couple barrels for me and they just wouldn't erode the throats. The treatment neither made the barrels shoot better or worse, they just last longer. MMi Tru Tec in Arkansa hired Joel to head up the SBN dept. They do a tremendous volume in military contracts now.
The bad part now is they don't do single barrels any more. I have gone another route to get mine done now.
inline6, my bud that I was speaking of is Dave Tooley in North Carolina. I have a buddy in Austin, Texas that runs my very few barrels when he has a bunch of AR barrels. Maybe you know Nez Rongero.

Butch Lambert said:

Joel Kendrick is originally from North Carolina. He is a past long range shooter of the year. Joel worked for a company that used the Melonite "Isonite" on their wear parts. It intrigued him and he started treating his long range barrels to make them last longer. He did a couple barrels for me and they just wouldn't erode the throats. The treatment neither made the barrels shoot better or worse, they just last longer. MMi Tru Tec in Arkansa hired Joel to head up the SBN dept. They do a tremendous volume in military contracts now.
The bad part now is they don't do single barrels any more. I have gone another route to get mine done now.
inline6, my bud that I was speaking of is Dave Tooley in North Carolina. I have a buddy in Austin, Texas that runs my very few barrels when he has a bunch of AR barrels. Maybe you know Nez Rongero.

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I do not know Mr. Nez Rongero but I most certainly know Mr.Dave Tooley.

One of my most accurate barrels I have ever had came from him (4 shots 3/8" @ 300 yards). He has a wealth of knowledge when it comes to gunsmithing and shooting.

I may have to try your buddy out. I would like to try melonite again but this time on a 25 CM.

Inline6,
I made arrangements for Shilen to donate barrels to the Texas State Junior shooters. Nez is doing the uppers for the team. Nez is a HM and has a Presidents 100. He is a very nice and generous person.
Inline6-Chev stovebolt or a Cummings?

Inline6 said:

I do not know Mr. Nez Rongero but I most certainly know Mr.Dave Tooley.

One of my most accurate barrels I have ever had came from him (4 shots 3/8" @ 300 yards). He has a wealth of knowledge when it comes to gunsmithing and shooting.

I may have to try your buddy out. I would like to try melonite again but this time on a 25 CM.

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Cummins

Yeah, I have 304,000 miles on my Duramax. By far the best vehicle that I have owned in 61years of driving. My buds with their Cummings like them except the ones that broke the mainshafts in the earlier manual transmissions.

I have had 2 Dmaxes. A 13 and a 16, the 16 had 120k when I traded it in (2 years old). It went in the shop 3 times for steering issues. I would have bought another if it had ac vents for the back seat riders. I bought a Maga cab this go around and the boys really enjoy the extra room.