The Barrel Burner

[STS]

I've been thinking about doing a post like this for a while that will serve as a good illustration of the erosive process in the larger case capacity to bore diameter ratio cartridges, aka 'barrel burners.' I have three .22 Creedmoor barrels that are at different stages of life that demonstrate this progression quite clearly. They also clearly show that some of the comments that are offered as fact regarding barrel burners, are not accurate at all. I want to keep this as short as possible so it doesn't turn into a dictionary length post so I'll post some info regarding the barrels.
1. All 3 barrels are Krieger .218 bore 8 twist 4 groove. I chambered all of them with the same JGS reamer with .110 freebore.
2. These barrels are on my predator rifles and have not been overheated in colony varmint fields.
3. Powder has been predominately VV N-160 with some Rl-26 also.
4. Barrel #1 is a chambered blank that I have waiting in the wings to replace barrel #3 when it officially dies. Round count is 0.
5. Barrel #2 has 598 rounds.
6. Barrel #3 has 1217 rounds.
Borescope image of barrel #1

 

[STS]

Borescope image of barrel #2 with 598 rounds.

 

[STS]

Borescope images of barrel #3 with 1217 rounds.

 

[L.Sherm]

Theres alot of circumstances that don't get factored into " barrel burners.
For 1217 rounds that barrel looks pretty good really.

 

[STS]

I had to break these up into individual posts to get it to work because of my poor computer skills. One of the take home messages that I am trying to convey is that the often quoted accuracy limit to the .22 CM is that it's an 800 round and done, throw it in the junk pile, cartridge. In my experience that simply is not factual. I have been blessed with some excellent barrels that have shot extremely well at long distance. The range that I shoot at most often is limited to 400 meters (430 yards) and each of the fired barrels would shoot sub 1 inch at that distance. Barrel #2 has turned in a few groups in the 1/2 inch range with some slightly less than that. Barrel #3 was shot at 500 yards last week and shot slightly less than 2 inches with 1217 rounds fired. It is still a very capable coyote rifle and has accounted for several over 500 yards this year. Hopefully this post will dispel some of the myths about the .22 CM and its hunger for barrel steel. I plan to use barrel #3 through next year and expect to get at least 1500 to 1600 rounds out of it before it fails to shoot well enough to count on it to perform its job at 500 yards or more.

 

[capitol]

Who cares what 1217 looks like. The only question should be does it shoot?

 

[RegionRat]

OP is obviously very good at bbl cleaning too.
Well done.

 

[mic2377]

Nice good to hear you are still getting decent accuracy approaching the end of life... What bullets are you shooting? Do you feel using N160 has been beneficial for barrel life instead of a more erosive powder (IE N555 or N560)?

I also just screwed together a 22 Creedmoor with a Shilen 7.5 twist ratchet rifling barrel, would be great if I could get the same life out of it.

 

[William Vogel]

Looks like you’ll get well over 2000-3000 rounds before it’s shot out.

 

[STS]

Nice good to hear you are still getting decent accuracy approaching the end of life... What bullets are you shooting? Do you feel using N160 has been beneficial for barrel life instead of a more erosive powder (IE N555 or N560)?

I also just screwed together a 22 Creedmoor with a Shilen 7.5 twist ratchet rifling barrel, would be great if I could get the same life out of it.

Looks like you’ll get well over 2000-3000 rounds before it’s shot out.

I'm shooting the 69 grain Lapua Scenar. It doesn't have the highest BC of the 22 bullets by far, but it has proven to be a very easy bullet to tune. and it shoots excellent groups at 700 yards and in. I have a bit of a different viewpoint on BC and velocity as it relates to hunting situations, so I'm pretty happy with that bullet.
I've started using N-560 in the last few months. An interesting note is that I saw an interview with a technical guy from Vhitavouri where he was asked a question that relates to your question about the single base vs. double base burning temperature. He quoted the temperature differences between the two powders and the take home message was that unless you were shooting extended strings of fire there would be so little difference it would be difficult to detect any difference in barrel erosion. He said if you are an F-class guy who cranks off a bunch of rounds in a short time frame, you probably should stay away from the double base powder. For my application where I have never fired more than 5 shots out of these barrels then there would likely be no difference in barrel life since the steel temp never gets that hot. I use whatever tunes the best, barrel life be damned.

Looks like you’ll get well over 2000-3000 rounds before it’s shot out.

I'm pretty sure it won't make it to 2000 rounds. I've roasted enough 22-250 barrels in my life to know that at 2.5K rounds they are getting toward the end of the road. One of the main goals of this thread was to dispel the myth that the .22 CM is no more than an 800 round cartridge. I don't intend to start another myth that it's a 2000 round cartridge either. None of these barrels will owe me anything if they die at 1500 to 1600 rounds.

 

[clowdis]

I'd say the throat on barrel no. 3 is very close to the end. I wouldn't think it would go very far past 1500 rounds. I'd also call a 1500 round cartridge a barrel burner. But it is at the point where a set back could extend the life quite nicely if you're into that sort of thing.

 

[ExPiney]

OP is obviously very good at bbl cleaning too.
Well done.

Perhaps he would be willing to share his cleaning routine?

 

[STS]

Perhaps he would be willing to share his cleaning routine?

I'll share my 'nothing special' cleaning methodology. First and foremost the most important thing is the use of a borescope. Your run of the mill Teslong is it. Without a scope you're guessing whether a barrel is clean or not. I use Ivey stainless rods and run a couple of saturated patches of Wipe Out with Accelerator to knock out any loose carbon and to begin to soften the remaining carbon. Then 3 or 4 breech to muzzle passes with a brush with Butches Bore Shine or Shooters Choice. I don't bring the brush back into the crown. Let it soak for a while and patch it dry then follow up with 1 or 2 patches of Iosso depending on what the bore scope shows me. While the solvent soak is happening I go after any carbon ring with a felt cleaning pellet (from Brownells) and a patch with Wipe Out that is jammed into the end of the neck and allowed to soak. The felt pellet is treated with a dab of Iosso and given a few twists of a old Dewey .17 caliber cleaning rod that I froze the bearings on and cut off to a length that's just slightly longer than the butt of the stock. That gets rid of any carbon ring as well as any method I've ever tried. All of this is nothing special really, just observation of the condition of the bore and addressing any stubborn areas accordingly.

 

[Evlshnngns]

I'd say the throat on barrel no. 3 is very close to the end. I wouldn't think it would go very far past 1500 rounds. I'd also call a 1500 round cartridge a barrel burner. But it is at the point where a set back could extend the life quite nicely if you're into that sort of thing.

STS, whats your take on setting it back? I only ask because you take meticulous notes and chamber your own.

 

[L.Sherm]

I know some smiths won't do it because they say the carbon dulls there reamer.
If I did my own gun plumbing I might consider it but your gonna get charged the same on an old barrel vrs a new one so is it worth it? I'm in the camp if I can't do it myself then I'm not

 

[STS]

STS, whats your take on setting it back? I only ask because you take meticulous notes and chamber your own.

A couple of thoughts. Back when I still shot in 100/200 BR matches I would set barrels back about .050 after 300 or 400 rounds. Keep in mind that the rate of erosion in a PPC case is nothing like the overbore .22 CM. I would have to set it back every 100 rounds or so to avoid dealing with a tapered, burned first half inch of barrel. I've set 1 or 2 back that had a fair amount of erosion and not been happy with the results. I dialed in the barrel as well as I could, took a skim boring bar pass to make sure I was trued up, and found out later with the borescope that the leade was clearly off center. I think it makes sense to do the set back to the PPC size cases if you can do it yourself. In my opinion it's not money well spent to pay someone to do that job. With a burner like a .22 CM it's not a sensable thing to do. Take off the junker and put on a new one. Shoot it until it dies and junk it too. Those guys up in Wisconsin make more barrels every day.

 

[357Mag]

I'm shooting the 69 grain Lapua Scenar. It doesn't have the highest BC of the 22 bullets by far, but it has proven to be a very easy bullet to tune. and it shoots excellent groups at 700 yards and in. I have a bit of a different viewpoint on BC and velocity as it relates to hunting situations, so I'm pretty happy with that bullet.
I've started using N-560 in the last few months. An interesting note is that I saw an interview with a technical guy from Vhitavouri where he was asked a question that relates to your question about the single base vs. double base burning temperature. He quoted the temperature differences between the two powders and the take home message was that unless you were shooting extended strings of fire there would be so little difference it would be difficult to detect any difference in barrel erosion. He said if you are an F-class guy who cranks off a bunch of rounds in a short time frame, you probably should stay away from the double base powder. For my application where I have never fired more than 5 shots out of these barrels then there would likely be no difference in barrel life since the steel temp never gets that hot. I use whatever tunes the best, barrel life be damned.


I'm pretty sure it won't make it to 2000 rounds. I've roasted enough 22-250 barrels in my life to know that at 2.5K rounds they are getting toward the end of the road. One of the main goals of this thread was to dispel the myth that the .22 CM is no more than an 800 round cartridge. I don't intend to start another myth that it's a 2000 round cartridge either. None of these barrels will owe me anything if they die at 1500 to 1600 rounds.

STS -

Howdy !

Apples, and near-apples:

For a long way time, I shot my own wildcat ".22-35 Remington ".
Case capacity 49.4gr H2O.

After years of using WW760 to propel Hornady 55SX from a 24"
1-14; I decided to try the ( then new ) VV560 high power energy powder; mostly because there was no " VV550 " back
then. When I called Kaltron-Pettibone for more specific info,
they cautioned that the high energy VV5XX series powders work best w/ heavier bullets in each calibre.

I still tried I under the 55SX, but attainable accuracy was much better when I used VV160. VV160 gave higher vel that did WW760 on balance, when comparing good accuracy that also acompanied good velocity w/ safe pressure.

I meantion all that because your chosen bullet is not really heavy for .224" cal, by today's standards. I will add that I also tried VV560 under Hornady 75 "A"-Max, in a 28" SS K & P
1-8 .224" cal; chambered also in my .22-35 Remington wildcat.
Range testing showed ( in my gun/my loads ) that AA3100 shot more accurately than did VV560....and that was with loads shooting in FED LR benchrest primers....and loads shooting
FED GM-215M. And yes, these days there are heavier .224" cal bullets than 75gr... but you are talkin' 69grainers.

I haven't had a rifle assembled ( yet ) that might exploit the virtues of VV560. I'm not knocking' the powder
YRMV .

With regards,
357Mag

 

[K22]

There is a lot published on the 243 Win being hard on barrels.

I've been shooting this cartridge since the mid 60's and reloading it since the late early 70's. I have owned a number of different brand 243 Winchesters.

Perhaps it is because of the way I shoot, i.e., cool bore sequences, but I have not found 243 Win to be any harder on barrels than any other similar bottle neck cartridge. This cartridge was designed as dual-purpose hunting cartridge.

Of course, if you are going to subject it to rapid fire sequences with maximum loads it's going to burn the barrel out quickly. Or if you take on a prairie dog hunt and shoot hundreds of rounds in a day, the barrel is going to be toast. In other words, if used for its designed purpose, it will last as long as any other similar cartridge.

The bottom line is that it is heat that is the primary element that accelerates barrel wear, so a lot depends on your fire sequence. Also, extreme overbore cartridges are also a factor but these too can be influenced by the manner in which they are shot. Therefore, it is difficult to make cartridge specific statements about barrel wear.

 

[bobcat93]

Wow..what an eye opener.

 

[STS]

I thought I'd add a short follow up to further illustrate just how wrong a borescope evaluation can be. Old barrel number 3, with that burned up cracked leade, was shot yesterday at the 430 yard mark. Rounds number 1228 thru 1230 yielded the following 3 shot group. It has a 1.5 inch dot aiming point and the 3 rounds measured .740. I'll put up the photos of the leade, and the target, as a vivid comparison of what a crap barrel looks like and how they can shoot if everything else is working. I did notice that the velocity was about 35 to 40 fps slower that it has been and I wonder if it needs a tenth or two more powder to get back in the node and see if some of the vertical will go away. I have never tested barrels with this degree of erosion for loss of velocity.