This is a long read but worth it. And a stable case for going to .260. This is not my article however.
"One of the big topics in the Gun rags is the new 6.5 Creedmoore cartridge. It's the usual yada, yada, yada. It's the latest and greatest so go out and buy one right away.
Lets look at the truth about the new cartridge (something you will not find in the gun rags).
Is it an accurate cartridge, yes. It has the potential (with modifications) to the rifle for shooting consistent ½ inch groups. But will an off the shelf rifle do it. Most likely it will not without modifications. More on this later.
Is it better than the .308. For all practical purposes, no. This statement you will never see in the gun rags.
The 6.5 Creedmoore development came about because Dave Tubb, a famous high power rifle shooter was looking for an accurate, efficient cartridge with low recoil which results in the low fatigue factor when shooting the national match course. This he achieved. But should the average guy scrape out his match grade .308 rifle for the newer 6.5 Creedmoore. I would say no unless your bank account is unlimited, as your gain in accuracy is hardly worth discussing. In my own testing the difference was barely noticeable between the match grade .308 and the Creedmoore. Recoil was slightly less with the 6.5.
Now here is the real draw back, and one that is not discussed in the Gun Rags. The barrel life with the 6.5 Creedmoore is a scant 4,000 rounds. Sounds like a lot of barrel life to the once a year hunter but to the target shooter as you are talking about less than a 2 year barrel life. The .308 will go at least 6,000 and if given good care can go as long as 8,000 rounds. This is from my experience and the experience of some of my fellow shooters that I have competed with.
As a matter of fact if I decide to someday get an AR in a 6.5 caliber is will not be in the expensive to buy 6.5 Creedmoore case but it would be in the .260 Remington caliber as I can make all the brass I want out of .308 cases which is much cheaper than buying the super expensive 6.5 Creedmoore cases. The .260 also has more powder capacity if I want to go to the heavier bullets. It must be remembered that the Creedmoore was designed to shoot the 120 grain and 140 grain pills not the heavier 160 grain bullets. Which by the way there is a very big lack of in the match grade bullets for sale by the bullet making companies. This of course is a very big mistake as the heavier slugs, even though they travel a bit slower would be better in the wind but the recoil would also be more of a factor.
With my various .308 match guns, given that you have a scope of 20 power or higher, a match grade trigger that goes off in the ounces, not the pounds and you are using match grade ammo will consistently shoot just a hair over ½ inch for 5 shots at 100 yards. The 6.5 calibers will consistently shoot ½ inch under the same conditions. But it will not do it with a stock AR15 gun with their very bad triggers. A match trigger (in the ounces) is a must for either the 6.5 or .308 calibers. This hardly justifies scrapping out any expensive match grade .308 rifle you may already own. Again this fair comparison will never been discussed in any gun rags. It is there job to sell new guns not give a fair analysis of any new cartridge or firearm that has recently come on the market.
Now we come to another problem in the AR guns. The trigger. Although Jewel makes an outstanding trigger for the AR .223 frame guns, it does not for the larger frame 6.5 Creedmoore gun. A quick call to the Jewell factor gave me the response that a person could install their trigger in the large frame AR15 but they would not guarantee it would not occasionally misfire. A friend of mine will soon do some testing on a .308 AR with the Jewel trigger to see if how many, if any misfires he gets.
Another call to a different trigger manufacturer by the name of Geissele stated that his trigger will work in the large frame AR guns. But here is the rub. My friend purchases the trigger and he was not impressed with it as much as the supper quality Jewel trigger.
One think I almost forgot to mention and that is that the Creedmoore cartridge is straighter and not as tapered as the .260 Remington. Gun-smithing 101 will tell you that a tapered cartridge has a tendency to feed better and extract better especially when the chamber is very dirty. Again the .260 Remington is the better cartridge.
The .260 Remington after becoming almost extinct in hunting rifles because of the lack of heavy bullets for it this round just may have risen like a Phoenix from its own ashes and have a new lease on life in target shooting. I think if the public and the ammo makers had been up on their history they would have realized that 6.5 cartridges like the 6.5 Rimmed Mannlicher and 6.5 Mannlicher-Schoenauer(rimless) were killing big game as big as elephants 100years ago and doing it with heavy 160 grain bullets a moderate velocities. Today with the "velocity is everything school of thought" any bullet traveling less than 3,000 fps is considered completely useless to all except the people have hunted all their lives with "classic cartridges" and know how good they really are."