6.5 Cm Vs 308 Barrel Life?

[okiefired]

Wasn't sure where to ask this so stuck it here.
  When velocity of the 308 an 6.5 CM are so close,  why is the expected barrel life so much shorter for the CM?  TIA.

[Aussie65]

Powder capacity is not that much less than a 308 yet you are forcing it all through a smaller bore which increases the speed of throat erosion.
If you maintain a cartridge size & decrease the calibre it will increase the speed of throat erosion.
Hence why say  a 257 WM is a a great hunting cartridge but you would need a standing order with a barrel manufacturer  if you used it as a target round.
In saying that though the 6.5 Creedmoor seems to maintain its accuracy to a very high level to around 2500 rounds or so.
Which compared to some of the 6mm cartridges at 800 or so is pretty good.

[Kadams1563]

I have to admit that 2500 rounds is a little disappointing. I did not do enough research when I started my build. I like hearing the .308 barrels lasting 5000+ rounds. I just hope the CM impresses me enough to replace the barrel.

[Aussie65]

I thought 308 was more like 10-12000 rounds?
How many rounds per year do you think you would shoot & in what discipline?

You may not need  a barrel replacement either it can be set back if you have the right barrel.

[eas1949]

Wasn't sure where to ask this so stuck it here.
  When velocity of the 308 an 6.5 CM are so close,  why is the expected barrel life so much shorter for the CM?  TIA.

6.5 Creedmoor barrels are made by the dwarven brothers Sindri and Brokkr.  The same brothers that forged Thor's hammer Mjolnir.  Just as they were done, Loki, disguised as a fly, bit Sindri on the elbow causing all 6.5 barrels forged to wear out at 4000 rounds but be extremely accurate

308 barrels are made by drunken Democrats from New Jersey .

[media id=1820 type=full align=center caption="Making 6 5 Creedmoor barrels"]

[Philbie]

I see Eric is enjoying his pain meds while they last.

[Danbonzo]

Wasn't sure where to ask this so stuck it here.
  When velocity of the 308 an 6.5 CM are so close,  why is the expected barrel life so much shorter for the CM?  TIA.

The more overbore the cartridge the shorter the life.
It can be calculated; case capacity in H2O grains divided by area (sq. in.) of bore cross section.
So a .308 Win would be
56(gr H20)/.0745= 751.67

While a 6.5cm would be
52.1(gr H2O)/.0548=950.72

For reference an ex. of real barrel burner 6.5-284
68.33/.0548=1246.89

It's generally accepted using this overbore scale that cartridges under 900 are relatively easy  while cartridges over 1000 are hard on barrel life.
Obviously the harder you drive the bullet by increased powder charge the more it raises the pressure which will impact the wear factor.
 

[Trent]

Round count is subjective. Depends on what you're using it for.

Competition... what kind, what distance, and at what level?

Hunting... what distance?

If you are competing at local 300yd matches I bet you're good to 4000 rounds. On the other hand, if you're competing on a national level at 1000yds you better be ordering a new barrel at about 1800 rounds so that you have it on hand when is time.

[Aussie65]

The benefits of the Creed outweigh the barrel life.
If your shooting  that much a new barrel isn't even worth worrying about.

[Cold Trigger Finger]

Yup,  it's not hard on barrels. . Definitely not an issue compared to enduring thru shooting 173 gr bullets at targets . Or heavier.
   6.5 Creedmoor RULES.
    308 drools
 

[Danbonzo]

Yup,  it's not hard on barrels. . Definitely not an issue compared to enduring thru shooting 173 gr bullets at targets . Or heavier.
   6.5 Creedmoor RULES.
    308 drools
 

Glen just concede and buy a 308 already, anyone who spends that much time and effort hating on a cartridge is just repressing his feelings. Really it's ok, we'll still respect you! "Resistance is futile"

[okiefired]

Thanks for the Info folks.  I'm fairly new to this forum but a long ways from it in shooting and reloading.  I knew pressure and velocity wears barrels but just was surprised the small difference would cut the CM barrel life to 25% of the 308. 
I'm not worried about it in the least and it's certainly no deal breaker to me.  I shoot quite a bit but have lots to shoot and putting 2500 rounds down  a single rifle will take me several years. 
Was just surprised by the difference,  that's all.

[michael1778]

Some numbers are getting thrown around on rounds in a barrel life, but I'm not seeing mention of barrels used in the identical situation with identical accuracy/consistency requirements.

So, let me put a question to the group of you that actually have fired these darn things over long periods of time.  Please pick a discipline for rifle use and then state what you have experienced for barrel life within the context of that same discipline.  For example, do people benchrest compete with both 308 and 6.5 Creedmoor?  If so, then please let us know how long you go before barrel replacement for the two cartridges.

People throwing around 10-12000 lifetime numbers may be talking about use in a much less stringent situation than where many of us do (or plan) to use the 6.5 Creedmoor.  My intuition is telling me that the 308 Win won't be 4x the life of a 6.5 Creedmoor when used for the identical purpose.  Somehow we got an Apples vs. Oranges comparison here?

Thank you.

[Danbonzo]

I'm thinking 10-12k may be a tad optimistic.

[Trent]

So my main competition is Metallic silhouette. We shoot out to 500 meters in a standing position. We generally strive for very high accuracy in our rifles, but we are realistic in the fact that we are shooting standing up with no support. So 3/4 moa is generally sufficient. I completely toasted my 7mm-08 barrel in just over 5,000 rounds shooting light charges of Varget. It was gone enough that I could push a bullet 1/4" completely out of the case before it would contact the rifling. It's accuracy went to shit right in the middle of a local match. Poof... done. The .308win is a little better but 10k to 12k isn't going to happen if you want any kind of accuracy. I have seen friends get up to 9000 rounds, but keep in mind that we all shoot very light loads compared to the general shooting public and we only shoot 10 shots per string in about a 7 minute span.

The 7BR on the other hand will exceed those numbers easily and still maintain 3/4 MOA.

My 6.5 Creedmoor silhouette rifle is still to low in round count for me to know how long it is going to go with the light loads.

My F-class 6.5 Creedmoor  (higher level of necessary accuracy) is at 1500 rounds and showing significant wear (hotter rounds and longer strings). Accuracy is still very good (1/2 MOA) but with the wear it is showing I expect it to crap out abruptly. Probably right in the middle of a match.

A ton of us shoot the 7mm-08 and 5000 rounds is the common life span in silhouette. They wouldn't last that long in f-class.