Home Forums Reloading Big Game Rifles 6.5 Creedmoor and 260 Remington velocity

Yep, similar to RL-17 before pressure-tested data came out.

Alliant's data for 26 shows it has perhaps a 100 fps advantage in certain cartridge/bullet weight combos, such as the .243 Winchester with 100-105's and the .270 Winchester with 150's. Maybe there's something else I missed, but other powders match 26 for velocity in most other combinations.

There's about 2 grains difference in case capacity, in favor of the .260. Since both cases hold around 50 grains of powder with a bullet seated, a 4% difference, this means there's about a 1% "advantage" in potential muzzle velocity for the .260 with the same bullet weights, on average, when using the same powders and bullets, loaded to the same pressures.

Obviously different rifles with vary slightly, but if you feel 1% is enough to go .260 (meaning around 27 fps with 140-grain bullets) then you should also consider the fact that long, high BC boattails can be seated near the lands in a 6.5 Creedmoor with a standard 2.84" magazine box, but not in a .260. Thus accuracy will usually be somewhat better in a Creedmoor with high-BC bullets, which makes up the 1% difference in potential velocity in less than 75 yards.

A longer magazine will solve this in a .260, but overall the Creedmoor has so many advantages these days that unless you want to use cheap .308 brass to make .260 cases, there's no reason to choose the .260.

I am sure many .260 fans will argue this, but I have experience with the .260 going back almost 20 years, and plenty with the Creedmoor as well.

Building a 6.5 Creedmoor or a 260 (or even the x57 cartridges) on a Mauser action (or similar length actions) and the advantage of the Creedmoor design lessens, again in my opinion.

(I own a few 722 and short action 700's BTW)

I’ve had a couple of both, in factory and custom guise. None of the factory rifles would kiss a VLD/AMax and feed it from a standard SA mag box with either the 6.5 Creed or the .260. When going custom.... it’s just as easy to specify what you’d like... so it’s a wash either way.

There is no difference between the two in the field... zilch.

The only advantages the Creed has... are excellent inexpensive factory ammo, and more rifles available.

Back to my original querry, where is the pressure tested data for the 260 / 6.5 CM and RL26?

I see lots of anectdotal data, where is the laboratory tested data?

Brad,
Here’s some factory data:

http://www.bergerbullets.com/pdf/6.5-Creedmoor-135gr.pdf

http://www.bergerbullets.com/pdf/260-Rem-135gr.pdf

Berger doesn't actually test loads with pressure equipment... they use Quick Load.

Factory or custom cut chamber?

It's now the official rifle loony Wonder Powder--it will always be reported as "I see no pressure signs"...........even when it turns out they're running 75k psi.........

IOn case anybody couldn't have guessed from my previous posts on this thread, anybody who actually worries about the difference in muzzle velocity between the 6.5 Creedmoor and .260 Remington needs to get a life. Even rifle loonies.

Dogshooter,

That's the dirty little secret of the 6.5 Creedmoor: The longest high-BC bullets can't be seated to the lands in some factory rifles, and still have the rounds fit in the magazine.

However, high-BC bullets just a little shorter will almost always work, such as the 139 Lapua Scenar. which is probably part of the reason that companies like Berger are making some slightly shorter-ogived bullets with BC's just about as high as the longer ones.

My present .260 (a Tikka T3) wouldn't even allow either 130 or 140 AccuBonds (the standard models, not the 129 or 142 LRAB) out to the lands.