Is 6.5 CM Really That Much Different than 260 Rem?

So assuming you reload your own ammo - what's the effective difference between these two rounds for a bolt gun with a 20 - 24" barrel?

Not much of a difference if you're loading your own. The 6.5CM (IMO) is best suited for the person that wants to get into the 6.5 game and NOT have to worry about loading their own.

One difference I'd read about was how the 6.5CM Hornady brass shows pressure signs prematurely (soft brass), while the Lapua brass for the .260 doesn't show that same tendency.

I personally don't know that much about the 6.5CM, so I'm curious as to what Yoda (E.Shell) has to say about the comparison.

The 6.5 CM has 0.07 gr of H20 more capacity, it's a shorter round, which means nothing to a bolt gun and it has a sharper shoulder, which may or may not translate into less brass growth.

Data is very close on the Nosler pages:
http://www.nosler.com/nosler-load-data/260-remington/
http://www.nosler.com/nosler-load-data/65-creedmoor/

The bullets are the same, though nosler used a faster twist on the CM.

If you want a big difference, look at the 6.5/284

BigDaddy said:

The 6.5 CM has 0.07 gr of H20 more capacity, it's a shorter round, which means nothing to a bolt gun and it has a sharper shoulder, which may or may not translate into less brass growth.

Data is very close on the Nosler pages:
http://www.nosler.com/nosler-load-data/260-remington/
http://www.nosler.com/nosler-load-data/65-creedmoor/

The bullets are the same, though nosler used a faster twist on the CM.

If you want a big difference, look at the 6.5/284

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Big difference, and a big reduction in barrel life as well.

BradMacc82 said:

Big difference, and a big reduction in barrel life as well.

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Cheaper than buying a Barrett .50 and there's more places that will let you shoot it.

BigDaddy said:

Cheaper than buying a Barrett .50 and there's more places that will let you shoot it.

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If I can afford a Barrett .50, then I can afford to shoot it at a range that's worthy of being graced by a .50BMG.

BradMacc82 said:

........I personally don't know that much about the 6.5CM, so I'm curious as to what Yoda (E.Shell) has to say about the comparison.

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Ed Shell = Yoda

ROTFLMFAO, never thought of Ed in that light before!!!

Lou45 said:

Ed Shell = Yoda

ROTFLMFAO, never thought of Ed in that light before!!!

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Well, I have gained a few pounds over the years, so I can understand the reference.

The .260 and 6.5 CM are about the same thing. It really boils down to what you like saying and want to tell your friends you have, or, a decision based on availability of your preferred rifle model. I see greater differences from rifle to rifle than I do between these two cartridges. The reloader will not notice a difference, the shooter will not notice, the target will not notice...

What I mean by this is that any rifles of the same caliber, .260 for example, can exhibit differences that exceed the theoretical differences between the two cases. One of my students is a custom gunsmith who turns out first class work. He built a pair of .260s at the same time, one for himself, one for his daughter. They both use Remington actions, and were both chambered to the same headspace spec with the same reamer, and both barrels are the same length. The ONLY difference is the barrel manufacturer, and with identical ammo, there is 100 fps difference between the two.

You can also develop greater velocity differences with barrel length changes.

With regard to case stretch, despite myth and legend, shoulder angle has very little to do with the rate of growth and is much more a marketing tool than a valuable attribute. The concept plays on intuition, not scientific fact.

If this was really a valid consideration, straight wall cartridges would have an uncontrollable amount of stretch, but yet, they just don't. They actually tend to stretch far less than bottleneck cases because we don't alter headspace every time we resize it.

The case stretches during firing, and the mechanism is that any headspace clearance will be taken out as pressures increase. More headspace (more aggressive full length sizing) = more case stretch. Zero headspace = zero stretch. While some small amount of stretch will be unavoidable, most case stretch "issues" are the direct result of an incorrectly adjusted sizing die.

With regard to Hornady vs Lapua brass, I have not seen either as being particularly soft, and my own experience indicates Hornady is a little bit harder. I had a reloading student Monday and Tuesday. We just ran through an OCW series for a new 6.5 CM, using Hornady brass, and we did not get any undue pressure signs, and actually ended up somewhat above book maximum.

Ed,

The voice of real world, hands on stuff!

Eff!!

First Obi-Wan Clandestine and now Yoda E.Shell. Would love to see their conversations together...

I keep trying to get them in the same place at the same time I will get video.

browning guy said:

I keep trying to get them in the same place at the same time I will get video.

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You mean they aren't the same person?

Lou45 said:

Ed Shell = Yoda

ROTFLMFAO, never thought of Ed in that light before!!!

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E.Shell said:

Well, I have gained a few pounds over the years, so I can understand the reference.

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It wasn't meant as a physical reference or such, but more in the respect that Ed has likely forgotten more about LR shooting and reloading than I currently know.

BradMacc82 said:

It wasn't meant as a physical reference or such, but more in the respect that Ed has likely forgotten more about LR shooting and reloading than I currently know.

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I have seen Ed look a little green

BradMacc82 said:

It wasn't meant as a physical reference or such, but more in the respect that Ed has likely forgotten more about LR shooting and reloading than I currently know.

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That's what I mean, Ed's a skinny li'l ol' phart.

I know, Yoda = mad balistic scientist = Ed.

Ed and I have met before. I worked on his CZ and he bought some crates from me.

As long as people understand that I'm many, many, steps below him, I'm honored to be mentioned with him.

For the longest time I have been wanting to take some courses from Mr Shell, but it's really hard for me to pull off.

clandestine said:

Ed and I have met before. I worked on his CZ and he bought some crates from me.

As long as people understand that I'm many, many, steps below him, I'm honored to be mentioned with him.

For the longest time I have been wanting to take some courses from Mr Shell, but it's really hard for me to pull off.

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That cz is sweet I have played with it several times!!

Be careful

browning guy said:

That cz is sweet I have played with it several times!!

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I heard you can go blind if you play with it too much. Damn it is hard to see the keyboard to type this.

babalou said:

I heard you can go blind if you play with it too much. Damn it is hard to see the keyboard to type this.

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Sounds like you have the same problem I have.........

sorry, whuuut?

Lou45 said:

Sounds like you have the same problem I have.........

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Wish the laptop screen was braille. Can't read a damn thing...