6.5 CM

[6878mm]

What advantage does the 6.5CM have over any of the older 6.5s
It`s basically the same as 260rem
And of course the swedish mauser round??

[bladeracer]

What advantage does the 6.5CM have over any of the older 6.5s
It`s basically the same as 260rem
And of course the swedish mauser round??

Advantages might depend on what you're using it for.
For me, the only tangible advantage over 6.5x55mm is that if fits in a modern short-action. But if you were planning to build a target rifle then you might want to go long-action anyway to use the longest possible bullets and maximise case capacity. If you're going to use factory ammo then the Creedmoor probably has advantages in choice of bullet, availability, and cost.
The biggest advantage for me to the 6.5x55mm is the military Swedish Mausers chambered for it, they shoot great, the M38 and M96 are some of the most accurate military rifles you can find.

[Wyliecoyote]

I do own all three cartridges and all three are very capable. If buying factory ammo without any intent to reload then the 6.5 CM is the pick. If reloading there are some considerations. Factory ammo for the CM uses proprietary powders that are not available to anyone. What that means is you will not be able to safely replicate and certainly not exceed factory ammunition velocity. I have exceeded the 140 grain bullet data but that is with Alliant powders that are not currently available. Attempts to get there with ADI powders were useless and often 150 fps behind the factory CM 140 ELDM loads. The CM is very capable but not with what we can use to reload it with in Australia.
As to the other two, the 260 is in the exact same boat with ADI stuff but it will exceed the CM data if full capacity and no 2.800" magazine OAL restiction is used. The Swede exceeds both with ADI powders.
So while the hype with the CM is everywhere, when it gets to handloading, the playing field really levels out. So the Swede is my pick for its ability to get real speed with 2209 and more specifically 2213 SC as the other two haven't the boiler room to get enough of the stuff in. Accuracy is all about the time one is willing to put into it but it should never be thought that the 6.5x55 is in any way less capable than the other two.

[6878mm]

thankyou

[straightshooter]

Not withstanding any of the previous comments each of the factory headstamped cases will be manufactured with a case head temper and construction appropriate to withstand SAAMI or CIP maximum average pressures. In the case of 6.5x55 it is about 50000 PSI and the 6.5 Creedmoor it is about 60000 PSI.
That does not mean the 6.5x55 won't survive the higher the higher pressure but it does mean you are doing so on trust that it will.

[SCJ429]

I have leaned on some Lapua brand 6.5x55 brass pretty hard and achieved some pretty impressive speeds and played with a 260 AI. But the CM has a more modern case design, and given the choice it is probably the pick of the three. If it is speed you want there are plenty of bigger cases that will get you there, like the WSM or RSAUM.

[Barbarian]

As others have said, good factory offerings. Sometimes when I’m short on powder it’s good to be able to fall back on a stack of Hornady Match.

Not super steep shoulder angle is usually a good sign of it not burning up barrels super fast though not the only consideration.

Action length isn’t as much of a consideration for me because I’ve only got tikka actions.

6.5 has good bullet selection, got a pill for everything.

Also when I couldn’t find any 6.5 Creed brass it was nice being able to make it out of .308 and 7.62 brass.

[SCJ429]

As others have said, good factory offerings. Sometimes when I’m short on powder it’s good to be able to fall back on a stack of Hornady Match.

Not super steep shoulder angle is usually a good sign of it not burning up barrels super fast though not the only consideration.
.

Not sure I agree that not super steep shoulders have anything to do with burning out barrels. A 260 lasts much longer than any 243 or 22/250, despite the same shoulder angle. Big case capacity, high pressures and fast rate of fire contribute to throat erosion.

[deye243]

As others have said, good factory offerings. Sometimes when I’m short on powder it’s good to be able to fall back on a stack of Hornady Match.

Not super steep shoulder angle is usually a good sign of it not burning up barrels super fast though not the only consideration.
.

Not sure I agree that not super steep shoulders have anything to do with burning out barrels. A 260 lasts much longer than any 243 or 22/250, despite the same shoulder angle. Big case capacity, high pressures and fast rate of fire contribute to throat erosion.

Yep the bigger the caliber for a given case the longer the throat life just look at the 308w same case as a 243w 260r but a lot more life .

[Barbarian]

As others have said, good factory offerings. Sometimes when I’m short on powder it’s good to be able to fall back on a stack of Hornady Match.

Not super steep shoulder angle is usually a good sign of it not burning up barrels super fast though not the only consideration.
.

Not sure I agree that not super steep shoulders have anything to do with burning out barrels. A 260 lasts much longer than any 243 or 22/250, despite the same shoulder angle. Big case capacity, high pressures and fast rate of fire contribute to throat erosion.

The way I had it explained to me was that the more square charge from acute shoulders like in a 6dasher or 6bra compared to the more gradual shoulder angle of .308w or 6.5C lead to things like higher pressures from more complete/even powder burn which cause more erosion with all other thing being equal. "Steep" probaby wasn't the right word.

Not that that the better powder burn from those doesn't help with consistiency, but no free lunch and all.

[Wyliecoyote]

Cartridge cases are a pressure vessel, not a cylinder head exhaust port, the bullet is the plug and the bore is the gas escape vent. Pressure is pressure no matter what the case geometry might be. In bottle neck cases the shoulder angle has a direct bearing on brass flow where the steeper angle generally has less flow and vice versa. A case that has 3cc volume, no matter what its shoulder angle might be, filled with powder will produce the exact same pressure as another case of differing geometry but with the same 3cc volume. The other thing about shoulder angles is said to be that steeper angles extend throat life. I know that not to be true because the 6 Dasher destroys throats in way less than a thousand rounds as does the 7mm SAUM. A Dasher has a 40 degree shoulder angle, the parent 6BR has 30. The Dasher uses 2 grains more powder than the the 6 BR with the same bullet weight, has a 30% shorter neck yet the 6BRs life span is in excess of 5000 rounds. What greatly extends throat life is neck length and that is a given irrespective of shoulder angle. The further you can keep the heat away from the throat, the better off you are.
Where efficiency comes into play is case volume paired with the right powder burn rate. That is where the real development has been over the years with so many powders to choose from. In specific regards to the 6.5 CM with 140 grain bullets, i can fill the case with 2209, damage it after one firing, and not achieve anywhere near the velocity i can with less pressure from Alliant Reloder 26 and a case that is hardly stressed at all. So the Creedmoor case is not the efficient part, the powder used is.

[ash_hendo]

What advantage does the 6.5CM have over any of the older 6.5s
It`s basically the same as 260rem
And of course the swedish mauser round??

If you're after a new rifle, there seems to be more choice in the 6.5CM. Still seems to be enough sweds around if you're buying european rifles.

Possibly more ammo for 6.5CM and the short action thing if that's important to you.

I do like my 6.5cm, but I would have liked a 260 rem too..... just the rifles I wanted were not available in that.

[Billo]

Having owned all 3 cartridges over the last 30 years, Id probably take a lightweight 260 Rem in a short action over a swede or a CM.

[in2anity]

What advantage does the 6.5CM have over any of the older 6.5s?

The advantage? I'll tell yu the simple reality of the matter; economy of scale. Every manbunner prs shooter out there drank the koolaid, and that's a huge market.


Is it an easier cartridge to use under wind(compared with say 7.62x51)? Same as the swede; abso-f-king-lutely! Just shoot through those wind changes and think and act like you're a pro

[Jorlcrin]

I've seen a LOT of roos lose their heads from a mates .260, and it's pretty darned accurate, and pretty darned effective.
95gn V-max pills are insanely explosive on roo craniums..

Having said that; when same mate bought a rifle for his teenaged son, he chose a 6.5CM for the benefit of (roughly) similar performance from a shorter action, and the son seems to have nailed some great shots with it.

If I was re-barrelling my 7mm-08, I'd consider .260, as I dont have any short actions to take advantage of the 6.5CM OAL.
If I was buying something new, I'd be tempted to go a 6.5CM.

I guess whichever way, I'd be happy with it.

[deye243]

6.5cm and 260r use the same action.

[Jorlcrin]

6.5cm and 260r use the same action.

Yep; My Bad.
They indeed are the same action.

Cant think why I'd believed the 6.5 was shorter; vague recollection of someone talking about the benefit of the shorter bolt-throw over the .260.

But that conversation was years ago that I heard it, and obviously incorrect.

Ahhh well; you get that.

[deye243]

Yeah not that it matters I built a 260 on a long action and there was no handicap on speed or accuracy .
In fact most long range hunting rifles are built on long actions and are just as accurate as the short jobs .

[jpsauer88]

None.

A 6.5CM is primarily all about keeping it short action length or target shooting.

If you dont care about either of those (i.e. you a hunting) then it is a poor design. I will get hate for this but let me explain. It shoots a slightly higher BC bullet at 308 speeds.

But when your hunting, energy is what you require.

Energy: A 6.5 produces lower energy within hunting distances (under 400m) compared to a 308
Projectile diameter: calibre and width is highly relevant to terminal performance, something overlooked. The force on a projectile is determined by the velocity and projectile diameter. A mono bullet for example (barnes, cx, gmx) will expand at lower velocities the wider it is due to the forces enacted on the projectile surface area.
Efficiency : The cartridge size/energy ratio is poor.
Preexisiting options: 260 provides no downside, rather downsides now are produced through factory twist options. I.e. a 22creed and 22-250ai identical in performance, capacity etc, but a 22creed will come with fast twist factory options as does a 6.5CM v a 260REM.
Monos: this is is own category, a 6.5CM can not achieve velocities required for a 300m shot with decent expansion using monos. Monos are a whole different kettle of fish as most rifles require light for cal to achieve good expansion. This is too limited on the 6.5 If i was forced to get a short action rifle for hunting I would get a 7mmWSM or 300WSM.

Finally, there is a point of optimal ratio for BC, weight, width and velocity for a short action/standard cartridge and that appears to be a 7mm, specifically a 7mm-08. Again I do not own one, just having researched this before and run calculations etc a 7mm-08 is the best of both worlds with the most optimal design for the 308 parent case.

I have owned a 6.5CM and do not own a 308 or a 7mm-08, so I do not have a horse in this race. But sold the 6.5 after reloading for it and realising the real limits of the cartridge, especially that i shoot monos when hunting.

[SCJ429]

There was a guy running around Africa, Uganda, called Karamojo Bell, at the turn of the century, shooting elephants and other game using a 7mm and a 6.5mm. His loads were far less powerful than any modern 6.5mm and bullet construction far from what we expect today. It seems to prove that a 6.5 can get the job done if you do your bit with bullet placement.

[straightshooter]

Reputedly Mr. Bell's preferred caliber was 7x57 although he on occasion used other calibers. I am not too sure that 6.5 was in the mix.
He specialised in putting a FMJ bullet into the correct spot of the brain of an elephant for an instant kill although be aware that he was always accompanied by a gun bearer with a loaded 4 bore rifle at the ready.
I don't really understand what this reference has to do with hair splitting over different calibers.
Although I do understand that we shooters do have our favorite calibers and of course mine is better than yours.

[SCJ429]

Reputedly Mr. Bell's preferred caliber was 7x57 although he on occasion used other calibers. I am not too sure that 6.5 was in the mix.
He specialised in putting a FMJ bullet into the correct spot of the brain of an elephant for an instant kill although be aware that he was always accompanied by a gun bearer with a loaded 4 bore rifle at the ready.
I don't really understand what this reference has to do with hair splitting over different calibers.
Although I do understand that we shooters do have our favorite calibers and of course mine is better than yours.

Mr Bell did use the 7mm on Elephants but also used a 6.5x53 on other African game. The post above mine was talking about the limitations of the 6.5 as a hunting calibre. I would have thought that any 6.5mm calibre shot at pigs, goats or deer at reasonable distances with good bullet placement would work just as well today as it did years ago for Mr Bell on African game species he was hunting. I hope this clears things up for you.

[bigpete]

He also nearly got himself and his offsider killed many years later trying the same stunts on elephant that had suffered a decade or 2 of ivory hunting and weren't the tame,placed animals he got his reputation on....

[Responsible_Shooter1]

Interesting thread, made me do some digging into it..

6.5 Creedmoor vs. .260 Remington

Design and Efficiency: The 6.5 Creedmoor has a shorter case and a steeper 30-degree shoulder angle compared to the .260 Remington's 20-degree shoulder. This design allows the Creedmoor to handle longer, high BC bullets more efficiently within a short-action rifle. This is great for long-range shooting and fitting in standard magazines.

Chamber Pressure: The Creedmoor operates at a higher max pressure (62,000 psi) compared to the .260 Remington (60,000 psi). This means it can achieve similar or better velocities despite having a smaller case capacity.

Twist Rate: The 6.5 Creedmoor usually has a faster twist rate (1:8) versus the .260 Remington (1:9), allowing it to stabilize longer, heavier bullets. This is crucial for long-range accuracy.

6.5 Creedmoor vs. 6.5x55 Swedish Mauser

Case and Action Length: The Creedmoor's shorter overall length allows it to fit in short-action rifles, unlike the 6.5x55 Swedish Mauser which needs a long action. This makes the Creedmoor more versatile with modern rifles.

Modern Ballistics: Both use high BC bullets, but the Creedmoor benefits from modern powder and bullet designs, giving it better velocities and energy retention at long ranges due to higher allowable pressures and a more efficient case design.

Recoil: Both have mild recoil, but the Creedmoor can be used in lighter rifles without significantly increasing felt recoil.

[SCJ429]

Interesting thread, made me do some digging into it..

6.5 Creedmoor vs. .260 Remington

Chamber Pressure: The Creedmoor operates at a higher max pressure (62,000 psi) compared to the .260 Remington (60,000 psi). This means it can achieve similar or better velocities despite having a smaller case capacity.

Twist Rate: The 6.5 Creedmoor usually has a faster twist rate (1:8) versus the .260 Remington (1:9), allowing it to stabilize longer, heavier bullets. This is crucial for long-range accuracy.

6.5 Creedmoor vs. 6.5x55 Swedish Mauser

Modern Ballistics: Both use high BC bullets, but the Creedmoor benefits from modern powder and bullet designs, giving it better velocities and energy retention at long ranges due to higher allowable pressures and a more efficient case design.

Recoil: Both have mild recoil, but the Creedmoor can be used in lighter rifles without significantly increasing felt recoil.

You can load both the Swede and the 260 to similar pressures and get similar velocity to the CM. Using Lapua brass I was able to push the Swede to some impressive speeds, factory CM loads would not beat them. I also used a 260 Ackley in a 30 inch barrel to shoot at longer ranges, it was very capable.
You can get yourself a 1:8 barrel and chamber it in the case that you want. Limited twist rate only applies to factory rifle offerings.
All these cases benefit from modern powders and bullet designs, there is no bullet that can only be used by the CM unless the twist rate of your particular barrel prevents you from shooting heavy VLD bullets.

[bigrich]

Cartridge cases are a pressure vessel, not a cylinder head exhaust port, the bullet is the plug and the bore is the gas escape vent. Pressure is pressure no matter what the case geometry might be. In bottle neck cases the shoulder angle has a direct bearing on brass flow where the steeper angle generally has less flow and vice versa. A case that has 3cc volume, no matter what its shoulder angle might be, filled with powder will produce the exact same pressure as another case of differing geometry but with the same 3cc volume. The other thing about shoulder angles is said to be that steeper angles extend throat life. I know that not to be true because the 6 Dasher destroys throats in way less than a thousand rounds as does the 7mm SAUM. A Dasher has a 40 degree shoulder angle, the parent 6BR has 30. The Dasher uses 2 grains more powder than the the 6 BR with the same bullet weight, has a 30% shorter neck yet the 6BRs life span is in excess of 5000 rounds. What greatly extends throat life is neck length and that is a given irrespective of shoulder angle. The further you can keep the heat away from the throat, the better off you are.
Where efficiency comes into play is case volume paired with the right powder burn rate. That is where the real development has been over the years with so many powders to choose from. In specific regards to the 6.5 CM with 140 grain bullets, i can fill the case with 2209, damage it after one firing, and not achieve anywhere near the velocity i can with less pressure from Alliant Reloder 26 and a case that is hardly stressed at all. So the Creedmoor case is not the efficient part, the powder used is.

That’s one of the best explanations of the technical side of things I’ve read. Neck length on cases is very important to me for tension on projectiles, and the “focus “ point of the powder burn is contained more in the neck than the chamber throat. I’ve played with a lot of different cartridges, 222 and 308 are my main choices cause of good case design, inherent accuracy, and long barrel life. I’m currently building a 250 savage, which if AI improved, is extremely efficient compared to other 25 caliber chamberings. I love the science of the shooting sports. To get back on topic, I had excellent accuracy out of a 6.5x55 tikka, but had brass flow problems into the bolt face with lapua brass and powder charges that should not have been a problem. The Swede case is a unique one as well. If I had my choice again, I’d have a tikka in 260 rem with the “M+” magazine tikka makes for the creedmoor that allows you to seat out to three inch COL . The 260 case can be easily made from 308 brass as well.

[bladeracer]

Where efficiency comes into play is case volume paired with the right powder burn rate.

And barrel volume.

[DMtrix]

Interesting thread..
If your using a long action and reloading just pick your favourite, have a barrel spun up to match your bullet preference and get on with it, the velocities are not going to vary hugely and while the older 6.5 sweed's are rated to a lower pressure the reality is a lot of people do run the newer actions considerably hotter than recommended (not that I would suggest it).

If you want to use a short action the 2 options are the 260 or the 6.5 CM of those 2 actions the 6.5 creedmoor will allow you to stick a long high BC bullet further out and still be able to fit it in a magazine and chamber it the tolerances on both are generally very reasonable.

I have utilised a 260 in the past and really enjoyed using it, though as above couldn't use the magazine due to a short action and had to single load to get optimal accuracy. I now run a 6.5CM it has good off the shelf ammo choice, plenty of reloading data available, is unlikely to go out of fashion any time soon meaning components should still be easy to find down the track.

DM

[SCJ429]

Cartridge cases are a pressure vessel, not a cylinder head exhaust port, the bullet is the plug and the bore is the gas escape vent. Pressure is pressure no matter what the case geometry might be. In bottle neck cases the shoulder angle has a direct bearing on brass flow where the steeper angle generally has less flow and vice versa. A case that has 3cc volume, no matter what its shoulder angle might be, filled with powder will produce the exact same pressure as another case of differing geometry but with the same 3cc volume. The other thing about shoulder angles is said to be that steeper angles extend throat life. I know that not to be true because the 6 Dasher destroys throats in way less than a thousand rounds as does the 7mm SAUM. A Dasher has a 40 degree shoulder angle, the parent 6BR has 30. The Dasher uses 2 grains more powder than the the 6 BR with the same bullet weight, has a 30% shorter neck yet the 6BRs life span is in excess of 5000 rounds. What greatly extends throat life is neck length and that is a given irrespective of shoulder angle. The further you can keep the heat away from the throat, the better off you are.
Where efficiency comes into play is case volume paired with the right powder burn rate. That is where the real development has been over the years with so many powders to choose from. In specific regards to the 6.5 CM with 140 grain bullets, i can fill the case with 2209, damage it after one firing, and not achieve anywhere near the velocity i can with less pressure from Alliant Reloder 26 and a case that is hardly stressed at all. So the Creedmoor case is not the efficient part, the powder used is.

The problem is that a 6BR barrel will not last anywhere near 5000 rounds, more like 2000 to 2500 depending on how you shoot it. This is exactly the same as a Dasher. Even I cannot destroy a Dasher barrel in 1000 rounds.
If neck length had anything to do with throat erosion, why does the 223 have the same barrel life of the much longer neck 222?
I am not sure why you are comparing 2209 to RL26, very different burn rates. But in regards to velocity, you should be able to get 2750 fps from a CM shooting 140s using 2209. If you think you can get more speed from a slower burn rate, try 2225 which is much less temperate sensitive than RL26.

[bigrich]

If neck length had anything to do with throat erosion, why does the 223 have the same barrel life of the much longer neck 222?

does it ? what studies have been done ?

(said with upper class british accent ) , 222 IS just better . it's what the intellectual , refined hunters, and connoisseurs of fine firearms choose

223's are for the mases of low brow peasants , and less cultured of our society and well , the 6.5CM , need i say anymore a 6.5x55 AI is far superior . and as a hunting cartridge , the 257 roberts is so much classier than that creed-more bohemian upstart

ps, this is just a tung in cheek p!ss take to lighten a sunday morning . don't take me seriously , i don't