Barrel Life

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matthewpauls

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I know this issue has probably been beaten to death already but I'm still confused. I have had people tell me it's the amount of powder burning/bore size and some people tell me how fast the bullet is going down the pipe. I've had quite a few people tell me that the barrel life on my 204 is the same as a 223. Well then why wouldn't the barrel life on a 6-284 be the same as a 284? Also had people tell me that an ackley will do better than the regular version of that cartridge as far as barrel life is concerned even though the bullet is traveling at a higher velocity. They say because of the steeper shoulder. Well, we all know the have a steeper shoulder, but why does that help barrel life,... if it does?? Thanks for helping the guy who doesn't catch on too quick -matt
 
I'm actually deciding on a 6.5 cartridge right now and I'm trying to decide if it's worth it to do a 260 rem instead of say a 6.5/06 ackley or 6.5-284 or possibly even just the 6.5/06 because of barrel life issues. I'm into hunting and precision shooting.
 
I have gone through 7 barrels with my 6.5 Mystic and 260 improved so can shed some light on the matter.

For F class, 1/2 MOA is getting a bit tired and this happens around 1200 to 1500rds depending on the luck of the barrel.

Very quickly you edge towards sub MOA by 1500 to 1800rds and from there it is pretty much a spray and pray pipe.

This burns 48 to 48.5gr of H4831SC and pushes a 139/140gr match bullet at just over 2900fps in a 28 to 30" tube.

Jerry
 
wow they sure go quick. That's interesting because I guess a 6.5-284 or the 06 ackley would burn em even just a bit faster eh? How does a 260 compare to the 260 ackley?
 
Barrel life on a .204 compared to a .223 will be night and day.

.204 will pooch at around the 1000-1500 round mark where a .223 will go into the multiples of thousands.

6.5-284 will make it to 1000 if you treat it right.

Jerry's 6.5 Mystic is pretty much an Ackley .260 so his numbers are pretty close to what you could expect, the regular .260 SHOULD go 1800-2500 rounds before chucking unexplainable fliers.

Ask Jerry about those funny fliers....."fun fun fun" as he would say. Right Jerry ;)
 
This may shed some light...

There has been a guideline that is in use by a number of different shooters that serves as a quantitative means of predicting barrel life. I will point out that the final number is an index, and double the index does not mean double the life....

Take the case capacity of a given catridge in grains of H20 and divide it by the surface area of the case mouth... SInce you used the 6-284 as an example, I'll compare it to the 6.5-284 anf the plian old 284.

284 Win: Case capacity = 66 gr. of H20 divided Case mouth area in sq. inches = 0.063345206

Overbore Inex is 1042

6.5-284 Case Cpacity 66 gr / case mouth area

Overbore Index -= 1205

6-284 = Overbore index of 1423!

To put this in perspective, a 308 winchester has an accurate life of roughly 7000 rounds and has an overbore index of 751

The 6BR is good for 2500 with an OBI of 815

The 6.5-284 is good for up to 1000 rounds with an OBI of 1205, so the 6-284 is ridicullously overbore and wqith an OBI of 1400+ is good for less than 700 rounds of ACCURATE life.

I have to say, the good old workhorse 260 is a pretty darned good cartridge if you hafta have a 6.5. ~2000 rounds of barrel life, the 140 Berger has a phenomenal ballistic coefficient, and you can easily get them up to 2850 with the right load. It (a 260) won the BC Provincials, the Lt. Governor's prize, came 2nd in the Western Canada F-Class Championships, and at our last match, a fellow shooting one for only the second time in his life shooting a centerfire rifle came in 4th out of 19 shooters (and even beat Mystic! :D)


Bigger is not always better, particularly for barrel life.
 
CyaN1de said:
6.5-284 will make it to 1000 if you treat it right.

Jerry's 6.5 Mystic is pretty much an Ackley .260 so his numbers are pretty close to what you could expect, the regular .260 SHOULD go 1800-2500 rounds before chucking unexplainable fliers.

Ask Jerry about those funny fliers....."fun fun fun" as he would say. Right Jerry ;)
Click to expand...

My suspicion is that the 260 over 1500rds will be AWESOME life. With only 2 to 4gr less powder, I can't see it increasing the life 50% but it would be great.

Fun, fun, fun....yeah, it sure was. Thanks for the 'light bulb' moment.

V V V V 5 V V V 4 (WTF!) 5 5 5 V V 4 (YEAH, WE BE HAVING FUN NOW).

When the barrel starts to throw flyers, it will drive you pleasantly insane trying to figure out where that 5mph gust came from that ONLY hit your target lane AND didn't move the mirage and wind flags

The best is when it 'blows' you the WRONG way :)

If you are competing, build a budget for a barrel or two more then you think you need and change BEFORE you have all this FUN, FUN, FUN....

Jerry
 
mysticplayer said:
My suspicion is that the 260 over 1500rds will be AWESOME life. With only 2 to 4gr less powder, I can't see it increasing the life 50% but it would be great.
Click to expand...

I quoted best and worst case scenario as I know Ron Herms shot his 6.5-08HABU (Same chamber Marc, Ian and I are using which is essentially a .260 Rem) to 2500 rounds before it went south on him.

1800-2000 can be expected but there are the exceptions both higher and lower.
 
Good for relative comparison BUT will not account for how the barrel is used in the real world.

You get to baby your barrel, dont's shoot them too warm, shoot in cooler temps, etc, etc.

Or you have a 22rds relay when it is 30C outside and your rifle has been lying in the sun for the last hour.

There is such a comparison on 6mmBR.com right now. You can cook a barrel in a day.

Barrel wear goes ballistic if you have to shoot your pipe very hot and for a longer period of time.

So a chamber combo that has XYZ for lifespan can be greatly decreased through aggressive use.

Keep in mind what accuracy means to the shooter. My 6.5 barrels were shooting in the 2's 95% of the time BUT the occasional flyer is simply unacceptable. Some shooters may not even notice this.

So barrel life has to come with some caveats.

Also, barrels fade in different ways. Some, like mine, toss flyers now and then even though the core group is still spectacular. Others will show a steady increase in the overall group size - this is much more desired way to loose a barrel.

Jerry
 
Mysticplayer,
I was going to ask, but you have answered it already I think. Does a barrel last longer, meaning more rounds, if a barrel is used more in hunting situations and some occasional targets? Meaning where it really never warms up or gets shot more than a few rounds in succession, and the barrel is allowed ample time to cool between rounds, would it last for higher round count?
 
Fire306 said:
Mysticplayer,
I was going to ask, but you have answered it already I think. Does a barrel last longer, meaning more rounds, if a barrel is used more in hunting situations and some occasional targets? Meaning where it really never warms up or gets shot more than a few rounds in succession, and the barrel is allowed ample time to cool between rounds, would it last for higher round count?
Click to expand...

ABSOLUTELY.

Used in this way, my rifles might last 2000rds with bug hole accuracy.

when you throw in lots of shooting in a short period of time and get the barrel too hot to comfortably hold....

You be burning it up :50cal:

Jerry
 
matthewpauls said:
I'm actually deciding on a 6.5 cartridge right now and I'm trying to decide if it's worth it to do a 260 rem instead of say a 6.5/06 ackley or 6.5-284 or possibly even just the 6.5/06 because of barrel life issues. I'm into hunting and precision shooting.
Click to expand...

Obtunded mentioned the overbore index that is used to estimate barrel life.
Here is a chart with some more cartridge values:
http://accurateshooter.net/Blog/overborechart4a.png

If you are thinking of a 6.5 and are concerned about barrel life, an interesting option is the 6.5x47 Lapua.

The 6.5x47 Lapua looks pretty good to me from a long range performance / decent barrel life perspective. In fact one of the design goals for this cartridge was increased barrel life for a 300m competition gun (European CISM). Yes I know 300m isn't considered far for many these days, but it's not like it falls out of the sky at 301m.

The 6.5x47 Lapua has an overbore index of 859 versus 977 for the 260 Remington and 1206 (!) for the 6.5-284. The Lapua has excellent factory ammo and of course excellent brass available. You can get very close to the ballistics of a 260 Remington. Put a slippery 123 or 139gr Scenar in it and engage targets a long way out. Stick a Barnes TSX in it and you could take a lot of North American game up to moose.

Here is a comparison between the Lapua and the 260:
http://demigodllc.com/articles/6.5-shootout-260-6.5x47-6.5-creedmoor/?p=1
 
Fire306 said:
Mysticplayer,
I was going to ask, but you have answered it already I think. Does a barrel last longer, meaning more rounds, if a barrel is used more in hunting situations and some occasional targets? Meaning where it really never warms up or gets shot more than a few rounds in succession, and the barrel is allowed ample time to cool between rounds, would it last for higher round count?
Click to expand...

I agree with Jerry. The vast majority of people with hunting rifles (some varminters will be the exception, and a few dedicated LR guys) will NEVER wear out their barrels, they just don't shoot enough. Most of the people I hunt with won't shoot a box of ammo a year. 5 rounds or so at the beginning of the season to make sure they can still hit something, and they're good to go. Takes a lot of years to wear out a barrel at that rate. - dan
 
I have ~ 200 rifles and shoot ~ 200 rounds per year. I am not going to wear out any barrels.

I may have never worn out a barrel, but I bought an old Rem700 22-250 that had a completely shot out throat. So someone did.

And I bought a take off barrel, a Krieger 6mmBRX that had inches of shot out throat I had to cut off.
 
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