Spreadsheet to Calculate Barrel Life

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Bart B, Aug 13, 2013.

1. Bart BWell-Known Member

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Found this Excel spreadsheet on calculating barrel life. It's pretty interesting in that it uses popular powder's heat potential in its formulas.

It's a SWAP; Scientific Wild Ass Prediction; not an exact number of rounds a barrel will last. But it does show that some cartridges wear out barrels faster than others. It doesn't provide input for how accurate someone shoots rifles nor the quality of the barrel and the ammo used in any accuracy test they conduct. It's based on pin drivers; they shoot more accurate than tack drivers. Most folks know that a military service grade semiautomatic rifle that averages 1 to 2 MOA accuracy at 100 yards will have a much longer barrel life than a pin driving competition rifle that averages under 1/4 MOA at 100 yards.

One thing that's sometimes held in contention is wear caused by the rate of fire. Some top level barrel makers that feel rapid fire with normal pressure rounds doesn't wear out barrels as slow fire use of high pressure rounds. Others think otherwise.

Excel Formula Predicts Useful Barrel Life within AccurateShooter.com

2. MontanaRiflemanWell-Known Member

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Interesting

I can't get the powder heat potential chart to open very far.

Looks like a 7mm burning 85 gr of average powder @ 60ksi is getting less the 700 rounds of life.

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4. Bart BWell-Known Member

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Neither could I see all the powder data, but I think they are all in there; they just can be scrolled up to see what the lower part of the data table has. If Mike comes across this thread, maybe he'll comment on that. What I do is remember or write down the powder potential, type it in then let it run.

After a good friend using Sierra Bullets' ballistic tech personal 7mm Rem Mag rifle set a record in the scope sight 1000 yard match at the 1970 Nationals, a lot of folks had to get one to shoot long range, Few understood why good accuracy dropped off bad in a hurry after 700 to 800 rounds. My own first long range match rifle was a .264 Win. Mag that lasted 640 rounds burning 72(?) grains of H870 under Norma 139-gr. nickel plated match bullets.

Last edited: Aug 13, 2013
5. MontanaRiflemanWell-Known Member

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It looks to me like that chart is bigger. It would be nice to know those other powder heat potentials.

6. MikecrWell-Known Member

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I wrote this a long time ago. That old version is less than perfect and I've asked 6mmbr.com to remove it as they've also posted newer versions. But the internet is sometimes unforgiving on getting rid of stuff.

If I had a way to post my latest here I would. If you'd like a copy email for it:
Mcrawford@ec.rr.com

I did a huge amount of research to form this and Bart is accurate in his assessment of it.
It does pass many many tests, as I have verified over the years.
The powder heat potential and pressure comes from QuickLoad.
Latest version calculates a line in the sand for shot rate, and I've dropped moly adjustment as nobody uses moly anymore.

Barrel life here is 'accurate barrel life'. That is a point where best accuracy, if reached, begins to drop(rapidly). Since most folks never actually achieve best accuracy from a barrel, most folks are late to see it's potential go bye-bye. That is, if the best you expect is 1moa from a 6.5x284, well then you may get 1moa FOREVER. If you reach 1/4moa with one, accept that you'll kiss that goodbye at ~1200rnds.
In contrast, BR shooters see it like a light switch was flipped.
If you group shoot quickly, your barrel's potential leaves quicker. If you shoot higher pressures, more powder, hotter powder, most overbore cartridges, barrel life is reduced. There is a price for everything.

One area that is not accounted for, as the data doesn't yet exist, is barrel life after Melonite treatment. This seems the best extension of life I've ever read about, potentially doubling even BR shooting barrel life.

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email sent

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me too