Barrel Life Expectancy Chart

[lte82]

Does anyone see anything flawed with using this chart for predicting barrel life between cartridges?

Having a conversation about a 6xc vs 260 rem, and I would've thought the 6xc would have much worse life span than a 260, but it looks like would be about the same according to this.

 

[DIBBS]

So many variables to consider! Rate of fire, single base vs double base powders, coated or nekkid boolitz etc would all factor into the equation to a degree. I don't know if the chart is accurate in prediction of barrel life, but it is interesting nonetheless. One would think the more grains of powder you burn the less your barrel life may be, but there are exceptions to every rule.

 

[clmayfield]

There is a spreadsheet here: Excel Formula Predicts Useful Barrel Life within AccurateShooter.com

As mentioned above, there are a lot of variables. You can give a 30-06 300WM life expectancy by loading it to 300WM levels. That said, it looks about right. I actually think the 30-06 should give barrel life similar to 223... but again, that is because most 30-06 loads don't take advantage of all of the case capacity. Design pressures are different for different cartridges, which explains why the chart may be a bit off.

 

[HodgdonExtreme]

I don't think that chart/algorithm holds water.

I think key cartridge/ ballistic parameters are:

Energy content of the charge
Bore cross sectional area
Pressure
Velocity

Which is to say nothing of barrel metallurgy or temperature...

I think wear increases fairly linearly as the charge energy/cross section ratio increases, but pressure may increase wear exponentially. Velocity is a small offset.

Just theorizing.

 

[6Dasher]

The chart shows volume vs bore, not barrel life.

 

[CMH]

The chart shows volume vs bore, not barrel life.

True. His post is asking if volume to bore area ratio is a good proxy for barrel life - i.e. is there a direct enough correlation to just use the above relative ranking of calibers as a barrel life chart.

 

[high right]

3 to 6 seconds in real time, depending on the cartridge of course.

 

[6Dasher]

[MENTION=45892]CMH[/MENTION]: It's only a factor if you use the volume for powder. The amount of powder (plus more factors) is a cause of wear. A larger case usually means more and slower powders, less efficient, hence overbore and the above chart.

He got the chart from 6mmbr.com where they also have an excel sheet that calculates (guestimates) barrel wear by entering caliber, powder weight and energy etc. It's all relative ofcourse, but gives a general idea into one caliber vs another. It also depends on what your demands are; if you want 0.25moa or better, or just 0.5-1moa accuracy, there are a lot of rounds between them.

 

[BigJimFish]

I agree with some of the others. The biggest issue I have with the chart is that, while many modern cartridge cases are loaded full and even to compressed charges, older ones such as 30-06 aren't. Put a 30-30 in your chart and witness how far off it is. Charge weight is more important than case volume to be sure. If anything, larger case volume has a mitigating effect on barrel wear given the same charge. I do think that plotting charge weight vs bore area would yield a rough guide to relative wear rates though, as others have mentioned, this would be rough as powder used and other variables do matter.

Honestly, I think the easiest predictor of barrel wear is probably simply velocity for the reason that, to some extent, it is a product of all the same variables that contribute to barrel wear.

 

[6Dasher]

Same powder in a larger volume also means a much lower velocity.

If you take a double based powder, you will need less for the same velocity, but it generally has a lot more energy which cancels out the benefit of less powder (and maybe still even has more wear). There's no one formula that can predict an exact amount of shots. Also think about the time between shots; the US f-class string shooting wears out barrels 30%+ faster than the EU version of paired shooting (more time between shots). Saying a 260Rem will last shorter than a 6.5Creed is kind of subjective, as we don't know what loads are being shot. If equal loads are used, it's not enough difference to worry about. etc.

 

[dondlhmn]

While the chart published above is interesting and does provide some very non-subjective numbers, I have found that, while higher bore to "available" powder volume ratios do mean you can put more powder in any given cartridge relative to the bore diameter, those folks that just HAVE TO push the limits of pressure pretty much all seem to have barrel life problems regardless of the caliber....some more so than others. Then, that is aggravated by some powders and really worsened if one insists upon high rates of fire. Cleaning habits can also enter into the barrel life equation, too.

 

[jakelly]

You also have to take into consideration case design.

 

[6Dasher]

How's that?

 

[Baluch]

Any Idea what the Barrel life of a Blaser R93 LRS 2 would be in .308 Win Using Hirtenberger's 190 gr Ammo having a BC of .55 & a Muzzle velocity of 750M/S .This ammo is MATCH SMK ,,they no longer manafacture this. This ammo has now been replaced by RWS Target Elite. I have a Brand New Blaser R93 LRS 2 & would like a rough idea less I start thinking of ordering a new barrel.

 

[6Dasher]

Same as any other 308.

 

[shortman308055]

Military is testing some of the new .300 mag sniper rifles beyond 20,000 rounds.... some even beyond 30,000 rounds with no accuracy loss as when tube was new........ kinda hard to believe myself but it gives me some hope for my new build...

 

[Deleted member 10043]

Does anyone see anything flawed with using this chart for predicting barrel life between cartridges?

Having a conversation about a 6xc vs 260 rem, and I would've thought the 6xc would have much worse life span than a 260, but it looks like would be about the same according to this.

What is the source for this chart? Or has that been asked?

 

[Deleted member 10043]

Military is testing some of the new .300 mag sniper rifles beyond 20,000 rounds.... some even beyond 30,000 rounds with no accuracy loss as when tube was new........ kinda hard to believe myself but it gives me some hope for my new build...

How did you get that information?

 

[rockbox]

Military is testing some of the new .300 mag sniper rifles beyond 20,000 rounds.... some even beyond 30,000 rounds with no accuracy loss as when tube was new........ kinda hard to believe myself but it gives me some hope for my new build...

Where do I get my hands on the magical barrels the military is using?

 

[6Dasher]

Depends and what "accuracy" you will accept. I've not seen 308's last that long, let along 300WM.

 

[Deleted member 10043]

So what do these numbers mean? John says: “My own conclusion from much reading and analysis is that cartridges with case volume to bore area ratio less than 900 are most likely easy on barrels and those greater than 1000 are hard on barrels.” John acknowledges, however, that these numbers are just for comparison purposes. One can’t simply use the Index number, by itself, to predict barrel life. For example, one cannot conclude that a 600 Index number cartridge will necessarily give twice the barrel life of a 1200 Index cartridge. However, John says, a lower index number “seems to be a good predictor of barrel life”.

?Overbore? Cartridges Defined by Formula within AccurateShooter.com

This article along with the Excel spreadsheet that 'clmayfield' posted are from the same Internet shooting magazine. The articles complement each other and linked together under "Related Articles". Note that the chart and the spreadsheet were created by that site's forum members, then in turn, the editors completed a narrative on the topics. So it is best to read them in their entirety because they explain that other variables are at play as well.

The comment I have is if the person that developed the spreadsheet simply backed into the formulas to get well known predicted results? If so, there is nothing wrong with that but he is not inventing the wheel here. However, if a person had the time he or she could develop an extensive chart based on these inputs using a base reference rifle set up. So,... the person that created the spreadsheet calculator done the community a solid by providing a baseline tool. There is nothing surprising in the overbore chart as well. Like the Geico commercial, "But did you know that a .243 Win is harder on a barrel than a .308 Win?" Nevertheless, the person that created the chart is least basing it on something tangible.

 

[The Gump]

Military accuracy standards must be pretty low.

 

[Cobracutter]

Military accuracy standards must be pretty low.

Most military sniper rifles hover around 1-1.3MOA for their accuracy requirement. This is the REQUIREMENT, many shoot better.

 

[damoncali]

Seems like a reasonable way to rank cartridges. The other variables (barrel material, flame temp, etc) don't matter as much because you don't necessarily care when you just want to figure out "which of these is more likely to last longer?".

As for the military, I'm staring at some old data that shows a 30,000-35,000 round life from a 7.62mm mini gun fired in 500 round bursts with 10 seconds of cooling between bursts. Of course, that's a different kettle of fish, but shows you what some exotic barrel liners/materials can do. (For comparison, a normal chrome plated cro-mo steel barrel lasted about 12,000 rounds at about 1/8 the cost). I don't think it's an unattainable goal at all to develop a rifle barrel that will hold 2 MOA or so for 20,000 rounds of .300 Win Mag.

 

[Deleted member 10043]

Most military sniper rifles hover around 1-1.3MOA for their accuracy requirement. This is the REQUIREMENT, many shoot better.

That makes me feel better about my own shooing ability

 

[6Dasher]

What is 2moa worth for every day or competition shooting? That's not really accuracy, that's just something coming out of a barrel going forward in the general direction of where you aimed.

 

[Deleted member 10043]

What does that have to do with barrel life?

 

[Cobracutter]

Seems like a reasonable way to rank cartridges. The other variables (barrel material, flame temp, etc) don't matter as much because you don't necessarily care when you just want to figure out "which of these is more likely to last longer?".

As for the military, I'm staring at some old data that shows a 30,000-35,000 round life from a 7.62mm mini gun fired in 500 round bursts with 10 seconds of cooling between bursts. Of course, that's a different kettle of fish, but shows you what some exotic barrel liners/materials can do. (For comparison, a normal chrome plated cro-mo steel barrel lasted about 12,000 rounds at about 1/8 the cost). I don't think it's an unattainable goal at all to develop a rifle barrel that will hold 2 MOA or so for 20,000 rounds of .300 Win Mag.

Last is not the same thing as firing for accuracy.

Plenty of CL barrels can exceed 20-30 or even 40K rounds and still fire well.

They aren't going to be half MOA guns however.

20K is a SHITLOAD for a precision weapon. The only one I knew of that approached those numbers and kept their accuracy are the FN SPR's and thats beacuse they have a thick ass CL barrel.

Bolt guns are also much more forgiving than gas guns beacuse they don't have to worry about gas port erosion. They also aren't fired as heavy/fast as bolt guns so heat does less damage to the gun.

I have a feeling that the future (or current for some) is going to be a nitrated barrel with a Carbon Wrap. Keep heat rentention down and a super hard finish on a very well made barrel/liner. The latest procurement of MK13 Barrels proves they are moving towards something similar based on the specs and requirements.

 

[Cobracutter]

What is 2moa worth for every day or competition shooting? That's not really accuracy, that's just something coming out of a barrel going forward in the general direction of where you aimed.

LOL. 2MOA in a variety of shooting posstions, conditions and ranges would be VERY VERY good for 99.99% of shooters.

Fucking internet discounts skill so much its funny. Everyone is a .1MOA shooter with a .05MOA rifle, banging victoria secret models... when they aren't island hopping on their yachts and playing $1M/hand baccarat.

 

[6Dasher]

Carbon is an insulator, it will keep heat in instead of dissipating it.

[MENTION=10043]Culpeper[/MENTION]: You first have to know what is acceptable to determine what "barrel life" means to begin with. If you're happy with 2moa then the barrel will last much longer than when you think at 0.5moa it is as good as toast. So it's all relative.


PS: I gues I am one of the 0.01%. We need to shoot 1/3moa from the bipod to have any chance of winning in our game, so a 0.5moa barrel is pretty much useless for my needs. My barrel will be toast long before that 99.99% even notice I guess.

[edited myself to keep it on topic]

 

[D_TROS]

LOL. 2MOA in a variety of shooting posstions, conditions and ranges would be VERY VERY good for 99.99% of shooters.

Fucking internet discounts skill so much its funny. Everyone is a .1MOA shooter with a .05MOA rifle, banging victoria secret models... when they aren't island hopping on their yachts and playing $1M/hand baccarat.

^^ Like button

I think the chart is a good BASIC start for barrel life. then it boils down to more advanced variables like seating depth, length of shooting (plinking to full auto), shooting conditions (ie dust storm), pressure from choice of powder, etc etc. Pretty much what Hodgdon said above.

BUT the bottom line is this, if you are worried about barrel life, more than likely you will never actually shoot out a barrel. It only takes the 2000 boolets you just purchased to realize how cheap barrels truly are; I spent more on gas to my last match than a new barrel. Shit the wine with dinner with my VIctoria secrete model cost more than a new barrel!!

Regards,
DT

 

[6Dasher]

Most people do not see a barrel as a consumable. Despite it not being the largest cost of shooting, there is a lot of hassle involved in setting up the new barrel and finding the right recipe again.

 

[Deleted member 10043]

6Dasher, It was your claim that 2 MOA is not even in the direction of the target that elicited my response about what does that have to do with barrel life. It may give people the false impression that 2 MOA is not good. I would hate to see somebody give up enjoying shooting because they can only consistently hit a 16" target at 800 yards. Even a maxed out barrel for "military sniper rifle" would provide 10" accuracy at that range. Let's be realistic. 1.3 MOA cited above is excellent. You belong to a small minority that shoot at a high level of accuracy to the point you are changing out barrels for no other reason. You said it yourself. You are not a good reference to rely on. You never keep one long enough to find out.

 

[The Gump]

Most military sniper rifles hover around 1-1.3MOA for their accuracy requirement. This is the REQUIREMENT, many shoot better.

1MOA just seems like a waist of a 300WM cartridge. It is at distance it makes a difference and IMO the 300WM is a cartridge to be used at distance so to me 1MOA is kind of, bla.

On the other hand, I'm fine with my AR shooting an inch.

 

[6Dasher]

Culpeper... I only switch them out when they no longer shoot what I want, not the cliche "replace after 1000 rounds to be sure". All barrels I have had die on me would start to show it at long range first, not grouping anymore and no longer that feeling of trust that the bullet goes where you aimed it and you know beforehand if you made an error (not withstanding my bad wind calls). So a barrel will be worn out for me sooner than for that majority, but I do not think that majority does not notice if the rifle only shoots 2moa groups.

What that has to do with barrel life, is that that is a relative term, depending on who you ask. Even if Joe Schmoe is shooting it at beer cans in his garden, I think he will eventually notice if his barrel can't hit that can anymore at 100y


PS: I select my cartridges for 100m prone on the lifetime criteria. Small cases, good brass, long barrel life. I've shot the 30BR since 2005 and it is one amazing case in terms of barrel life. Also ran a 7.62x39 in 308 bore that would have lasted pretty much forever had I not sold the complete rifle to fund another project.

If you are worried about barrel life, as mentioned earlier by others, than you should stick with the 308. If better scores are important (better ballistics in the wind), then you will have to compromise in the shape of barrel life.

 

[Deleted member 10043]

That's more better, thanks.

 

[Cobracutter]

1MOA just seems like a waist of a 300WM cartridge. It is at distance it makes a difference and IMO the 300WM is a cartridge to be used at distance so to me 1MOA is kind of, bla.

On the other hand, I'm fine with my AR shooting an inch.

This is the ignorance and internet skill modifier +8 I was reffering to.

 

[damoncali]

1MOA just seems like a waist of a 300WM cartridge. It is at distance it makes a difference and IMO the 300WM is a cartridge to be used at distance so to me 1MOA is kind of, bla.

On the other hand, I'm fine with my AR shooting an inch.

Just the opposite, actually. The longer the range, the less accuracy is required of the rifle. Ballistic factors dominate the dispersion at range - namely range uncertainty, velocity variation, and most importantly, wind. The rifle's inherent accuracy plays a relatively small part. A 2 MOA win mag is not ideal (1 would of course be better), but the difference in terms of ability to hit a target way out there is slight.

The closer your'e shooting, the more the rifle matters.

 

[The Gump]

This is the ignorance and internet skill modifier +8 I was reffering to.

Mmm Ok.

1. Your logic makes zero sense. If it did then why do all top competitive shooters use rifles that are capable of much more than 1 minute. Why bother working up hand loads?

2. You Mr. Omnipotent don't know me from Adam. PERIOD. So with this simple FACT in mind, how do you know how well I do or do not shoot? Fuck! I just answered my own question by addressing you as Mr. Omnipotent. My bad.

3. Since you are Mr. Omnipotent you know who Brian Litz, his latest book on accuracy and precision, and the chapter in that book that covers this very topic.

 

[The Gump]

Just the opposite, actually. The longer the range, the less accuracy is required of the rifle. Ballistic factors dominate the dispersion at range - namely range uncertainty, velocity variation, and most importantly, wind. The rifle's inherent accuracy plays a relatively small part. A 2 MOA win mag is not ideal (1 would of course be better), but the difference in terms of ability to hit a target way out there is slight.

The closer your'e shooting, the more the rifle matters.

I actually disagree with you as well but you were not a dick about it so I'll leave it at that.

The points you address are talked about in Litzs' book as well.

 

[6Dasher]

I also don't agree with that. My targets have the same scale at each distance, so the same accuracy is required preferably. No more, no less (relative to distance). At longer ranges you have more factors influencing what you hit besides the inherent accuracy of the rifle/cartridge, very true; atmosphere and velocity/bc deviation between shots etc. That does not take away you will want the same accuracy to start out with from rifle/cartridge/shooter. That last one is a pita!

 

[damoncali]

It's a matter of relative importance. For ELR shooting, the rifle matters *less* than it does point blank range. At 100 yards, the rifle's inherent accuracy may account for 75-80% of the dispersion. At 1200 yards, it will be a good deal less. If the wind is +/- 4 MOA, and the range is +/- 1.5 MOA, it doesn't much matter if your rifle is 1/2 MOA or 1 MOA.

 

[Deleted member 10043]

Mmm Ok.

1. Your logic makes zero sense. If it did then why do all top competitive shooters use rifles that are capable of much more than 1 minute. Why bother working up hand loads?

2. You Mr. Omnipotent don't know me from Adam. PERIOD. So with this simple FACT in mind, how do you know how well I do or do not shoot? Fuck! I just answered my own question by addressing you as Mr. Omnipotent. My bad.

3. Since you are Mr. Omnipotent you know who Brian Litz, his latest book on accuracy and precision, and the chapter in that book that covers this very topic.

The Litz bug-a-boo


Sent from my C771 using Tapatalk 2

 

[The Gump]

The Litz bug-a-boo


Sent from my C771 using Tapatalk 2

Excellent rebuttal.

 

[The Gump]

It's a matter of relative importance. For ELR shooting, the rifle matters *less* than it does point blank range. At 100 yards, the rifle's inherent accuracy may account for 75-80% of the dispersion. At 1200 yards, it will be a good deal less. If the wind is +/- 4 MOA, and the range is +/- 1.5 MOA, it doesn't much matter if your rifle is 1/2 MOA or 1 MOA.

At the end of the day all of the topics you bring up (M.V. variation, wind, etc.) effect what happens down range and are valid points. That being said, this thread started out with barrel life expectancy and when to change a barrel. Then we got on to accuracy standards of the rifle. And finally we got into M.V. variation, wind, me the shitty shooter and my internet +8 ignoramous skill set.

I have Litzs' book in front of me now and according to him you are correct regarding inherent accuracy of the rifle. According to Litz there is a more improved hit percentage inside of 500. That doesn't mean outside of 500 there is no increase. According to Litz and his models on a 10" at 1K there is a 15% increase in hit percentage with a .5moa rifle over a 1.5moa rifle with a 175smk@2700.

 

[damoncali]

At the end of the day all of the topics you bring up (M.V. variation, wind, etc.) effect what happens down range and are valid points. That being said, this thread started out with barrel life expectancy and when to change a barrel. Then we got on to accuracy standards of the rifle. And finally we got into M.V. variation, wind, me the shitty shooter and my internet +8 ignoramous skill set.

I have Litzs' book in front of me now and according to him you are correct regarding inherent accuracy of the rifle. According to Litz there is a more improved hit percentage inside of 500. That doesn't mean outside of 500 there is no increase. According to Litz and his models on a 10" at 1K there is a 15% increase in hit percentage with a .5moa rifle over a 1.5moa rifle with a 175smk@2700.

That's all I'm saying - the further you shoot, the less help a really accurate rifle is, and the more a really accurate wind estimate is. More accurate is always better, of course.

 

[shortman308055]

How did you get that information?

im sorry, i made a mistake.....it was actually the 7.62 round that was tested beyond 20,000 rounds.... i looked up m24 sniper weapon system on google then clicked on wikpedia.... 300 yard accuracy was held to 3.8 inches if i remember correctly.... not benchrest quality, but after 20,000 rounds id say thats freakin awesome

 

[6Dasher]

[MENTION=50186]damoncali[/MENTION]: I agree on the wind being more of an influence beyond a certain point.

 

[The Gump]

That's all I'm saying - the further you shoot, the less help a really accurate rifle is, and the more a really accurate wind estimate is. More accurate is always better, of course.

So lets say you have a 1.5moa rifle. I guess my question is, how are you supposed to trust your initial zero? In my opinion you would need to shoot like 15 rounds to have a trusted zero.

 

[damoncali]

So lets say you have a 1.5moa rifle. I guess my question is, how are you supposed to trust your initial zero? In my opinion you would need to shoot like 15 rounds to have a trusted zero.

You do it exactly the same way as with an accurate rifle. It won't take more shots, it will just be a bigger group.