308 = 2650 fps. / 6.5 Creedmoor = 2710 fps. Why 1/2 the barrel life?

[Nomad0001]

When I first heard about this issue years ago, I thought it was the 6.5 was going 4,000+ fps or something like that. Turns out 140 gr. ELD is only going 60 fps faster than 175 gr. 308. Yet people still say 5000+ round life for the 308 and around 2,500 round life for the 6.5 barrels respectively.

Someone please 'splain to me. Thanks.

 

[2c1fr]

Ttrl

 

[runngun]

The barrel is being worn by the gas, not by the bullet. The same amount of gas is going through a smaller hole.

 

[padom]

Haven't seen a 6.5/260 Bartlein accuracy drop at 2500rds yet but also not running super hot loads either. 2815-2850 range and still sub 0.5moa 5x5 over 4000+ rounds and I know one guy still getting those results over 5000rds..

 

[Forgetful Coyote]

Kinda off topic but what do yall think of the new Lapua brass for the creed? Able to reliably run higher charge pressures and get any meaningful MV gains without trouble?

 

[ocabj]

Kinda off topic but what do yall think of the new Lapua brass for the creed? Able to reliably run higher charge pressures and get any meaningful MV gains without trouble?

I run Lapua 6.5mm Creedmoor brass in a 24" 1:8" Shilen.

Berger 130gr AR Hybrid + 43.5gr H4350 + Wolf SRM = 2900fps
Berger 140gr Hybrid Target + 42.0gr H4350 + CCI BR4 or Wolf SRM = 2750fps

I really haven't tried to push. I went to 42.3gr H4350 with the 140gr and saw it average 2763fps.

 

[Sheldon N]

The barrel is being worn by the gas, not by the bullet. The same amount of gas is going through a smaller hole.

+1

This is why the 308 has more barrel life than the 6.5 Creed. The more hot burning powder you put into a smaller space the more it erodes the throat of the barrel.

 

[flyright]

I've got a buddy with close to 4000rds (3920 something last I heard) through a factory Savage LRP barrel and that thing is still shooting .2's and .3's - same as when it was new. He is still using the same bto length also. His COAL is 2.83 - I think. About a quarter of those rounds have been factory Hornady and his handloads are not slouching either.

 

[Nomad0001]

+1

This is why the 308 has more barrel life than the 6.5 Creed. The more hot burning powder you put into a smaller space the more it erodes the throat of the barrel.

Thanks. I really had no idea this was the reason. I pictured what was wearing was the grooves in the rifling...

 

[elephantrider]

Barrel life has more to do with the volume of powder vs. the bore/throat size that it is burning through since it is essentially flame cutting the throat on each shot. The throat/lead are what gets worn out on a barrel that is properly cared for. Thre are other factors such as case shoulder angle, powder burn rate, and the powder heat of combustion, but primarily it's powder volume vs bore size.
Good article:
http://www.accurateshooter.com/technical-articles/overbore-cartridges-defined-by-formula/

 

[Praeger]

The barrel is being worn by the gas, not by the bullet. The same amount of gas is going through a smaller hole.

The 6.5mm bore is about 27% smaller than the bore of the .308.

 

[LRI]

Powder choice seems to have some input as well.

 

[Mr.Tacticool]

My old friend Speedy always said there is little point in long barrel life it if comes in package with long odds ........

 

[bentbolt308]

Don't it also depend on abuse too? Like a hunting rilfe 10-20 rounds a year VS comp rilfe shooting 80-100 rounds in few hours of time.

 

[Silvan]

When I first heard about this issue years ago, I thought it was the 6.5 was going 4,000+ fps or something like that. Turns out 140 gr. ELD is only going 60 fps faster than 175 gr. 308. Yet people still say 5000+ round life for the 308 and around 2,500 round life for the 6.5 barrels respectively.

Someone please 'splain to me. Thanks.

I burnt .308Win for 8500 +. Factory ammo 175 gr, 2600 fps. You are pessimistic with 5000 and 2500.
6.5 CM is still supposed to be workable up to 4000 +.
6.5 runtime is less because of smaller caliber (ID is less), volume and type of powder (thermobaric wear) as some gentlemen mentioned too.
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