Barrel burners? The real numbers.


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Kachok
June 21, 2012, 10:19 AM
OK the term barrel burner has been thrown around ALOT lately so I though a little scientific breakdown is needed to see which cartrages are really excessively overbore by measuring their powder to area ratio. All loads reflect an average of the max loads with heaviest bullet in each. Most of these are on the warm side at leased but I threw in the 308 seeing as it has a very long well known barrel life.

22-250 913gr/sq in 36gr
243 948gr/sq in 44gr
25-06 1059gr/sq in 55gr
6.5x55 840gr/sq in 46gr
6.5-284 950gr/sq in 52gr
264 win mag 1042gr/sq in 57gr
270 win 912gr/sq in 55gr
270WSM 1077gr/sq in 65gr
280AI 900gr/sq in 57gr
7mm Rem Mag 1011 gr/sq in 64gr
308 win 605 gr/sq in 46gr
300 win mag 881gr/sq in 67gr
300WSM 855gr/sq in 65gr
300 Ultra mag 1184gr/sq in 90gr
So here is the breakdown
600-700 Don't worry your grandchildren will likely be shooting from that barrel.
700-800 Still pretty mild by any standard.
800-900 Always let your barrel cool between strings if you want many years of service, getting hot.
900-1000 Hard on barrels regardless of cooling, but acceptable barrel life can still be had.
1000-1100 Barrel burner alert, with these expect to start loosing some accuracy quickly, often before you hit 1,000 rds
1100+ Buy stock in Shilen because all of your money is going to them if you shoot alot.
There are other factors involved too like barrel heat, brass design, and peak pressure but they are minor compared to the volume of burning abrasive being forced down your barrel at supersonic speeds.
If anyone else would like me to run the numbers of their pet cartrage/load just let me know.
I hope this clears things up for us a bit.

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taliv
June 21, 2012, 11:06 AM
i think there are several additional factors that contribute. for example, angle of the shoulder

MtnCreek
June 21, 2012, 11:13 AM
.22 x .50BMG. Figure about 225 grs of powder. :)

jim243
June 21, 2012, 11:20 AM
All loads reflect an average of the max loads with heaviest bullet in each.

This has me confused. My interest is in the 243 you have listed. My standard load for this is with a 95 grain SST, not a 40 grain bullet. And my fps should be around 2,900 not the 4,000 that you can get with the 40 gain bullet.

How can you say that you are using the heaviest bullet in each??? Or do you mean the lightest in each??

Also I use the standard of 130 grain in the 270 not 55 grains, I save those for the 223.

Jim

MtnCreek
June 21, 2012, 11:26 AM
I think the grain listed is powder charge.

jim243
June 21, 2012, 11:30 AM
I feel like the church lady from SNL, "Oh, never mind".

Jim

USSR
June 21, 2012, 11:40 AM
Nice chart, but meaningless. Too many other variables such as bullet weight, amount of powder, and type of powder (single base or double base) that will skew the numbers profoundly.

Don

Kachok
June 21, 2012, 11:49 AM
This has me confused. My interest is in the 243 you have listed. My standard load for this is with a 95 grain SST, not a 40 grain bullet. And my fps should be around 2,900 not the 4,000 that you can get with the 40 gain bullet.

How can you say that you are using the heaviest bullet in each??? Or do you mean the lightest in each??

Also I use the standard of 130 grain in the 270 not 55 grains, I save those for the 223.

Jim
Yeah that is 44gr or powder not a 44gr bullet. That is using a 100gr projectile which depending on the type of powder used you will max out at 42-46gr so I used the 44gr figure, does that make sense?

Kachok
June 21, 2012, 11:52 AM
i think there are several additional factors that contribute. for example, angle of the shoulder
Yeah I think I said that, it looked alot like "There are other factors involved too like barrel heat, brass design, and peak pressure" Sharper shoulders and long necks help no doubt, but they don't fix a 1,000gr/sq in ratio either.

SpeedAKL
June 21, 2012, 12:20 PM
I've been told some of the biggest barrel burners are the .378-series Weatherby Mags and other mega-magnums (RUMs, .338 Lapua, Lazzeronis, etc). Any experience with therse?

Kachok
June 21, 2012, 12:32 PM
I've been told some of the biggest barrel burners are the .378-series Weatherby Mags and other mega-magnums (RUMs, .338 Lapua, Lazzeronis, etc). Any experience with therse?
No hands on, but looking at the numbers the 30-378 Wby is just as bad as the 300 RUM and the Lazzeroni 7.82 Warbird is even worse 118gr of powder through a .308 bore is a whopping 1,552 gr/sq in!! The 338 Lapua is not as bad as some think, it only ranks about a 992gr/sq in which while hot is only a little more intense then a 270 win, mil spec rating on their barrels was 5,000rd if I remember correctly.

rajb123
June 21, 2012, 12:41 PM
I always tought the 22-250 was a mega barrel burner..... according to your chart ....not so much

Kachok
June 21, 2012, 12:46 PM
^ Two reasons for that, one is that any Varmint caliber is likely to get called a barrel burner because people shoot so many rounds downrage often in a rapid fashion. Two is that the 22-250 is one of those cartrages people like to push over max loads, I have seen it several times where people are trying to push 4k fps. Those guys are the first to cry about having to get another barrel.
Any cartrage used in any varmint hunting or match shooting is much more likely to be labled a barrel burner vs a big game hunting cartrage that we are in no hurry to shoot and might only go through a couple boxes of ammo a year. I will bet you anything my 270WSM barrel won't be shooting 1/2 MOA 1,000rd from now, but since neither varmint hunters nor match shooters use it I doubt it will ever become commonly called a barrel burner. 1,000 rd might last me the next 10 years as long as I don't use it as my main target rifle.

valnar
June 21, 2012, 12:56 PM
^ I also heard that there is some 'extra' physics thrown in on the smaller bores that increase wear compared to larger bores. What that factor is called, I do not recall. But I think empirically people will admit that the smaller bored barrels are indeed ones that get replaced more often.

jim243
June 21, 2012, 02:40 PM
But I think empirically people will admit that the smaller bored barrels are indeed ones that get replaced more often.

Easier to shoot, less recoil more rounds down range.

As an example, I can shoot 40 grain (243) bullets at 4,000 fps and get 750 rounds down range before my accuracy falls off, or I can shoot 95 grain bullets at 2,900 fps and get 1,500 rounds before accuracy falls off.

You can choose how fast or slow you burn your barrel out.
Jim

Skyshot
June 21, 2012, 02:52 PM
Good chart, I think heat and pressure accelerate the process more than any other factors. Having said that I have a 7mm Rem Mag that has over 3k rounds through it and it still shoots sub 1/2 moa (5shots too) a 100yards. I keep waiting for it to go so I can rebarrel, but it's hangng in there. Also a 243 barrel that has over 2k rounds through it and they were smoking hot loads. But it also is still a tacker.

Kachok
June 21, 2012, 02:57 PM
Good chart, I think heat and pressure accelerate the process more than any other factors. Having said that I have a 7mm Rem Mag that has over 3k rounds through it and it still shoots sub 1/2 moa (5shots too) a 100yards. I keep waiting for it to go so I can rebarrel, but it's hangng in there. Also a 243 barrel that has over 2k rounds through it and they were smoking hot loads. But it also is still a tacker.
What brand of barrel is that?? Most 7mm rem mags I have seen start dropping off at half that! Are you running full power loads or are you well under max?

Skyshot
June 21, 2012, 03:12 PM
The 7mag is a 1971 Remington factory barrel, and no I don't shoot full power loads in it. Its always shot best in the mid-range of charges with IMR4831 and IMR7828 and the bullets have always been in 140 to 160 gr. weights. When I would increase charges it would open up so I took the "if it ain't broke don't fix it" attitude. I'm sure it's close to being on the verge, but as I have gotten older I don't shoot the big 7 as much. It's just relegated to deer hunting on cold clear days.

joed
June 21, 2012, 05:03 PM
I don't know if I agree about people pushing the .22-250 loads. Most of the loads I've seen on here aren't much faster then a .223.

Me, I push the .22-250 for all it's worth. If I wanted a .223 I'd have bought one. I wanted a .220 Swift and I'll try to get as close to it in performance as I can.

willypete
June 21, 2012, 05:38 PM
I wanted a .220 Swift and I'll try to get as close to it in performance as I can.

Sooooooo why didn't you just get a .220 swift? :confused:

Kachok
June 21, 2012, 05:45 PM
Hard to find 220 Swifts now, 22-250 has stolen it's thunder to say the least. There is only about a 100fps difference between them anyway.

Arkansas Paul
June 21, 2012, 05:46 PM
Sooooooo why didn't you just get a .220 swift?


Not trying to speak for joed, but probably because there are very limited options in .220 Swift these days and nearly unlimited ones for .22-250. Just a guess.

Ridgerunner665
June 21, 2012, 09:59 PM
Shoulder angle and neck length both make a difference on throat wear...true...but nothing makes a bigger difference than the amount of hot abrasive getting blown through there with every shot.

Somebody up there (I forget which post...read it earlier today) has this backwards....pushing light bullets to max velocity isn't near as hard on a barrel as pushing heavy bullets to max velocity.

In truth...velocity itself has absolutely nothing to do with it...

With light bullets one can use faster powders, that means LESS powder...to get the most velocity from heavier bullets require large doses of slower powders...and with that, you're pushing far more abrasive through the throat.

An example....243 Win, 75 grain Sierra bullet, 40 grains of Varget...thats a pretty high stepping load in terms of velocity (3,200 fps from the 20" barrel on my 243), but very easy on the barrel. I know this because that is my coyote load...A deer load that I worked up for a buddy of mine...243 Win, 90 grain Nosler Ballistic Tip, 35 grains of Varget...3,100 fps, still easy on barrels.

Another contributing factor to throat wear...solid copper bullets (Barnes), and solid gilding metal (Nosler E-Tip) is even worse...these can have a pretty big impact on throat wear too and is just another one of many reasons to fight lead bullet bans.

Kachok
June 21, 2012, 11:06 PM
I don't know Ridge I have seen both light/fast and heavy/slow burn barrels out pretty quick. Max loads for lighter bullets can be just as much powder if not a little more, max load for a 40gr 22-250 is 46.5gr of H380, max load for the 60gr bullet is 44gr or H4831sc similar results when comparing 243, 7mm-08 and others

Ridgerunner665
June 21, 2012, 11:19 PM
Yes...but you can pick your powders and use less of it...

For the 22-250...either Benchmark or IMR 3031 will work for the 40 grain(I used Varget when I had a 22-250)

And for the 60 grains...H4895 and H322 are great.

The point was you can still get all kinds of speed with faster powders and light bullets (and its more economical to do so).

Even the 30-06, with 125 grain bullets...53 grains of H4895 will get the same velocity and will probably be just as accurate as 57 grains of Varget...all the while being easier on the barrel.

Jim Watson
June 21, 2012, 11:23 PM
There is a neat little spreadsheet for calculating barrel accuracy life on the 6mmBR site.
It considers caliber, powder charge, powder type, and chamber pressure.
Results will be a lot below what is commonly claimed, but bear in mind this is for competition accuracy. Competition WINNING accuracy.

About halfway down the page at:
http://www.6mmbr.com/BlogSept2005.html

Ridgerunner665
June 21, 2012, 11:28 PM
I guess I should add that I am as much a promoter of high load density as anybody...it generally helps accuracy...and for a hunting load that I'm not going to shoot hundreds of rounds of such as my 30-06 (168 NBT, 58 grains of H4350) I prefer a full case...thats a big game round though, slow fire is the norm.

For my 243...my chosen varmint rig...its actually a youth gun, a pure joy to carry, easy to maneuver in the blind, and delightfully accurate...Varget is the slowest powder I use (and in the 243, its at the fast end of the scale)...just have barrel life in mind when you decide on a load.

Kachok
June 21, 2012, 11:29 PM
"Yes...but you can pick your powders and use less of it...

For the 22-250...either Benchmark or IMR 3031 will work for the 40 grain(I used Varget when I had a 22-250)"

While that is true, there are heavy weight loads that work with relativly small powder charges, like 60gr of IMR 4064 in a 300 win mag, that is 10-23gr less then other powders and pushes 180gr to 3000fps! I use larger powder charges then that in my 30-06.

Ridgerunner665
June 21, 2012, 11:41 PM
Yep...that 300 WM load is an extreme example...but a good one!

That 300 WM load will yield barrel life comparable to a 30-06...With load density that low though, it may be a bit fussy where accuracy is concerned...or maybe not...never know until you've tried it.

Kachok
June 22, 2012, 12:00 AM
Yeah usually I get better groups with higher load density, but I have seen exceptions to that rule too. Some very low density loads in standard calibers work best with a magnum primer to ensure a good burn. Handloading is something of a crash course in physics, we don't use all the science lingo but we learn the principals pretty quick :)

Elkins45
November 24, 2012, 10:24 AM
According to the barrel life spreadsheet, my 257 Weatherby should be getting pretty close to dead by now. I have settled on 72 grains of Reloder22 behind a 90gr Hornady GMX bullet as my standard hunting load.

Sheepdog1968
November 24, 2012, 12:02 PM
Thanks. Just curious where the 30-30 and 45-70 sit. I suspect it's at or below the 600 level.

USMC8541
November 24, 2012, 12:30 PM
Surprised my 270 is way up there. More reason to buy a 308

1858
November 24, 2012, 02:15 PM
AccurateShooter.com has a chart based on case capacity in grains of water divided by the bore cross section area in square inches. They also have a link to a spreadsheet to calculate useful barrel life.

http://bulletin.accurateshooter.com/2008/10/spreadsheet-formula-calculates-useful-barrel-life/

http://bulletin.accurateshooter.com/2011/04/overbore-cartridges-a-working-definition/

http://accurateshooter.net/Blog/overboreindex2011.png

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