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Range Report Wh at is it about the 6.5 cm that causes short barrel life?

stradibarrius

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Minuteman
Dec 2, 2017
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I am wondering what ballistically that cause the 6.5 cm to have a short barrel life. It isn't a magnum, the powder charge is not that high???
 
Stupid people who run it at 70000 PSI
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What do you consider short barrel life? Short with respect to what other cartridge?

The reason the barrel life of a 6.5 Creedmoor or .260 Rem is less than that of a .308 is that they are overbore cartidges.

The secret to getting more barrel life out of a specific cartridge, as mentioned by 918v, is keeping pressures down. Don’t shoot at the ragged edge just to get an extra 100 FPS. That’s why some will get 3000+ good rounds and others will only get 1200 from a like barrel.
 
Trying to beat a .308 with it. 🙂

Seriously, pushing a lot of gas down a little bore. Compare the Mil Spec .30-06 (similar to .308) to a commercial .30-06 and a .308. All three will have a different barrel life. Then look at a .25-06 same volume smaller throat.
 
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Well, its pretty much the same amount of gas as a .308, but it is all trying to get out of a smaller bore hole. Any resistance to gas flow, especially close to the chamber, means torched surfaces over time.
 
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I think the issue is that the 6.5CM was developed and marketed as a replacement for the 260 Rem. It is capable of doing that, but in order to make up for reduced case capacity; the commercial loads have to be hotter to deliver comparable performance. The smaller case capacity needs to fill a bore length that's just a tad more for the same barrel length. Similar charges in a smaller chambering adds up to more heat and pressure in the throat. It may not seem like much; but a difference is a difference, and it shows up with roasted throats.

IMHO, its marketing success is based as much in good performance as it may be in bad marketing on Remington's part.

When barrels burn, it is as much about the marketing strategy as it is about internal ballistics.

Whether it's with bigger case capacities like the 6.5-284, or hotter loadings like the 6.5CM; it seems to me that the problems tend to set in when folks try to mess with success. We 260 shooters understood that the 6.5-284bn was winning, but also that it was at the price of throat life. It may be turning into a similar result for a different reason with 6.5CM.

I think both of these chamberings suffer when they attempt to treat the case capacity like they treated the 308. The narrower diameter bore requires a longer length in order to properly process the propellant charge of roughly the same volume. I don't really think the 260 is really an overbore cartridge, and rate it as similar in that respect to the .30-'06. It may be that it's a very compatible chambering for the 6.5 bore diameter and that altering it may also be a drift away from that adequate formula.

Lengthening the bore is my answer to throat decay; 24" isn't enough, 26" is better, and I favor 28". In order to maintain an efficient pressure curve; it's probably better to use a slower burn rate, too.

This is an opinion talking; just mine.

Greg
 
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There are several definitions for overbore. Hot loads too fast kill barrels prematurely. Heat is the killer. You're supposed to be playing sniper so no more than three shots per session. Don't stay in place longer than that unless you have a lot of support including CAS.
 
Yea I am above average at something in my life goal achieved 3600 round of 6.5 creedmoor and still from what the barrel thread looks like more than 1/2 of its life left baby and still shoots like a champ crossing fingers for another 3600 or more rounds .honestly think the shooter and how they shoot can make a difference I only shoot 10 round strings taking a break to let it cool down every so often and never let it get too hot , also gives me a chance to practice dry firing a lot more also giving the barrel time to cool with a chamber chiller , I like dry firing far more but either work pretty well so far . god knows I can use all the practice I can get behind the trigger and breathing and at what point I should squeeze the trigger or not and watching what the wind is doing all with an internal monolog yelling at me that I am doing it all wrong yea .
 
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243 & 22-250 are also not magnums and look at their barrel life...

I'm pretty sure it's the 45ish grains of powder burning down the small 6.5mm bore that give it its barrel life...
 
Yea I am above average at something in my life goal achieved 3600 round of 6.5 creedmoor and still from what the barrel thread looks like more than 1/2 of its life left baby and still shoots like a champ crossing fingers for another 3600 or more rounds .honestly think the shooter and how they shoot can make a difference I only shoot 10 round strings taking a break to let it cool down every so often and never let it get too hot , also gives me a chance to practice dry firing a lot more also giving the barrel time to cool with a chamber chiller , I like dry firing far more but either work pretty well so far . god knows I can use all the practice I can get behind the trigger and breathing and at what point I should squeeze the trigger or not and watching what the wind is doing all with an internal monolog yelling at me that I am doing it all wrong yea .
I abuse my 260 barrels regularly and they get 3000 or close to it.
I can see a 6.5 CM go further easily with moderate ammo and some care.
 
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