243 Win vs. 6mm CM... Another redundant Cartridge from Hornady?

I had it explained why the 243 was known as a barrel burner, was to do with the shoulder/neck angle combo that directed hot gases directly to the chamber area just beyond the brass, the leade took the brunt of the heat
idk, not a rocket surgeon me
243 is a bit overbore, that's the only reason for throat erosion.
Weatherby shoulder is sharper and more efficient then any of these 40 degree affairs, don't see any of those shoulders on new cartridges.
308 doesn't have a sharp shoulder, and those barrels will out last a 6cm by 2 or 3 times, but it's not overbore.
 
When the 243 was designed, it was tossing a completely different bullet than what you can get today. Since then bullet design has changed dramatically. 6cm is designed to throw the modern high bc bullets (long and heavy for caliber) available today without worrying about cartridge overall length. Twist rate, tighter chamber tolerance, factory match ammo etc.

That being said there is something special about a 58gr vmax doing 4k out of a 243.
Kind of like shoving an 85 gr JHP Sierra bullet out of my 6.5 x 55 SE "doing 4k" (or close to it; very flat shooting for varmints. Ground hogs and Coyotes.
 
Its an easy button answer to shoot heavy match bullets (including factory) with properly cut chambers for them accurately, and the twist rate, affordibly and not going custom.

If you wanted to do the same for 243, good luck. Yes you can load them to the same performance. But you're not gonna find much 243 Win ammo that can do that, and you're likely going to have to rebarrel a 243 Win. There are more 1:8: twist rifles out there like Tikkas and Rem 700s, which is great, if you want a Tikka or Rem 700. Most ain't.

But if you do, and you like handloading anyway, and you have the mag box length to run the heavies you want...then yeah. 243 Win is every bit the equal.
Stevens 334 is an 8 twist 243 iirc. Nice to have an affordable option. Factory ammo is still an issue though.

I wouldn't sell my 243 but if I was getting a new rifle in either caliber it'd be the 6 cm. See many 260s around these days?
To be fair you never saw a lot of 260s around. 264cals never really caught on until recently.
 
Stevens 334 is an 8 twist 243 iirc. Nice to have an affordable option. Factory ammo is still an issue though.


To be fair you never saw a lot of 260s around. 264cals never really caught on until recently.
I still have mine, and it shoots very well. No longer have it's direct predecessor though, the 6.5 Panther. I also still have a 6.5x55, and a 6.5-06 and a 6.5x54. I've owned many 6.5 Swedes over the years, and they really opened my eyes to what those 6.5 bullets can do. In the past I have also owned 6.5 TCU, 6.5x68, 264 Win and 6.5 STW. You are correct that it the bore was never as popular as the 30's and 7mm's though. - dan
 
Stevens 334 is an 8 twist 243 iirc. Nice to have an affordable option. Factory ammo is still an issue though.


To be fair you never saw a lot of 260s around. 264cals never really caught on until recently.

Lookin at their websites they're 1:10" :(
 
Boooo. The dealer I was looking at had it listed as 1:8. Happy I didn't pull the trigger now, already have a 10 twist 243.

Oh, good thing!

Maybe they had a 1:8 version and dropped it? Either way...yeah. Woulda been cool. Low price of entry for what looks like a very accurate rifle.
 
When the 243 was designed, it was tossing a completely different bullet than what you can get today. Since then bullet design has changed dramatically. 6cm is designed to throw the modern high bc bullets (long and heavy for caliber) available today without worrying about cartridge overall length. Twist rate, tighter chamber tolerance, factory match ammo etc.

That being said there is something special about a 58gr vmax doing 4k out of a 243.
Special in that your barrel only lasts 2000 rounds....
 
6 CM cartridge design is superior to the old Whinny - Better coal and less brass stretch ! Comes with a 8 twist barrel .
Won’t out perform a 243 but I feel it’s a Better cartridge design .
Nothing wrong with a 243 Win . JMO RJ
Agree on all points. Same can be said about the 6.5CM.

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It's absolutely wild how many people look at a new bench rest cartridge and go "this is redundant" or "the gain is only a couple hundred FPS" without realizing that the target market is not replacing every 243, 260, 6.5 creed or whatever else. While we're on the subject it's ridiculous just how many people try to put down the 6.5 creed because "the 6.5x55 exists" totally ignoring it's a higher pressure cartridge that neatly fits perfectly into short actions.

These calibers are for bench rest shooters who rebarrel every single season as a rule and spend thousands of dollars each year trying to not just get get decent groups but send every round through the same exact hole.

They're living in a world where the dies they use cost almost an order of magnitude more than Lee's that will get the job done for 99% of shooters out there, use laboratory analytical balances that go to four decimal points, already match grade brass and bullets are hand sorted for weight/concentricity, and use all manner of black magic rituals and blood sacrifices to get their rifles shooting the way they do. Things most people don't even think about like the case capacity, geometry, and shoulder angles are all fussed over.

At the point when you're already rebarreling frequently getting into a new caliber is just a new set of dies and some brass. With all the time, effort, and money that already goes into competitive accuracy shooting it's frankly trivial to switch to the new latest and greatest chambering offered.

The goal isn't to replace the 243, it's chasing the ultimate in accuracy competing with other guys trying just as hard to do the same.
 
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Just put together a new rifle a few years ago and went through these same thoughts. I went with the .243 mainly because I had a set of dies and a bunch of reloading components from previous .243's, both of those .243's seemed to shoot exceptionally well. I did have the luxury of ordering a barrel with my choice of 8 twist so that is a big factor there. AT the time I was also looking at the 6mm Sherman which is still on my one day/ maybe/that's a cool cartridge list. If i was buying a factory rifle in 6mm caliber for target shooting I probably would have chose the 6 creed.
 
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