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

6mm GT seems like a better fit for that role than the Creed
Maybe so, but I was able to pick up brass for the 6 CM at the nearest outlet. Same with dies. I had another guy wanting a 6CM barrel, so he could offset the cost of the reamer, and I suspect I'll get more calls for 6CM than I would for 6GT. The truth is, I could just as well have simply made a 6mm-250 and accomplished much the same thing (I've had that reamer for 45 years) but the CM made sense from a practicality standpoint. I chambered my first 6.5 CM when there was a brief shortage of brass for my 6.5x55. The ready availability of good brass made it worthwhile. Ultimately, the brass case is nothing more than a container for the powder and a gasket for the breech. The designation doesn't mean a lot.
 
I might just get a 25 cm barrel spun on my current 6.5cm when it dies, but I would rather buy more components than a new set of dies I reckon.
 
From the Family Archives, the back reads:

"This is my old 30-06 Winchester made into a 6MM with a 22" barrel and a new stock etc. It has an 8" twist barrel and uses 110gr + 120gr bullets instead of 90gr which KG's gun uses.".

Screenshot_20250429-172103.png
 
I can see both side of the coin when it comes to cartridges like these. On the one hand, it drives me nutty to hear people talk of a cartridge as having a twist rate applied to it.
A cartridge/chamber are an entirely independent selection from the twist rate of the barrel blank they may be paired up with. The .223 is an extreme example of this where common twist rates vary from 14 down to 7.

That said, the majority of rifle factory’s have chosen to produce 243 rifles (among others) in slow twists and with short throats which hampers the use of long heavies in those barrels. At the same time, ammunition companies haven’t been seemed keen to offer heavy for caliber (modern, high bc) ammunition in this cartridge. (Obviously the both rifle and ammo makers would need to get on this page to together for this to be successful)

Now enters the other side of the coin:
Oh wait, they did!
And at the same time they shortened the cases so they would run in AR10mags in free countries…
And by offering good quality, high bc factory ammo, AND marketing the heck out of it, they’ve brought in a whole new generation of long range shooters who didn’t have the experience to hand load or the budget to get custom rifles put together. Of course these new kids are likely to regurgitate all the propaganda, er, I mean marketing they read regarding the unprecedented, innovative brand new invention known as their cartridge and how it’s different and better than anything that came before it because, ‘science’. And that of course gets old.

But in the end, more options, new shooters and increased interest in long range is a decided win in my book and nothing’s stopping me from putting together a classic chambering in a fast twist barrel and building my own ammo like Ive been doing anyway.
 
Here to tell you that a fast twist 243 shoots long bullets very well. I run 112 grain match bullets in my 8 twist 243 with great results.

I’m sure that the 6 creedmoor is a great cartridge. After all the cartridge itself is very similar to the 243. The big change was the barrel twists.
The change was far more than barrel twist.
 
The change was far more than barrel twist.
I know there were other changes like shoulder angle and higher pressure on published loads (at least in the hornady manual). Outside of a small gain in brass life span for reloaders I do not understand where the gains were made in a different shaped cartridge with roughly the same displacement.

I run off of the belief that pressure multiplied by area equals force. But I’m no genius so I could very well be wrong.

I am assuming with a comment like that, you may have information that the rest of us do not.

Care to share it with the rest of us?
 
Well no, it isn’t just that. Magazine OAL is a pretty big deal. Good brass is a pretty big deal, good chambers are a pretty big deal, dies that match chambers seems to be a pretty big deal, SRP options a great, and the list goes on. Shoot what you like. But don’t tell me none of this stuff matters or makes a difference
 
I’d imagine it makes a difference to the PRS/NRL and other dynamic long range shooters that top the charts with these new fangled cartridges. And don’t give me the “kiddos want to try new things” better than half the shooters at these matches are over 40
 
Well no, it isn’t just that. Magazine OAL is a pretty big deal. Good brass is a pretty big deal, good chambers are a pretty big deal, dies that match chambers seems to be a pretty big deal, SRP options a great, and the list goes on. Shoot what you like. But don’t tell me none of this stuff matters or makes a difference
Are we talking about differences between the 6mm creedmoor cartridge design vs the 243 design? I think we are getting mixed up here.

I sure do agree that all those things you listed matter in the rifle platform that you are building. You can do all that with a 243 or 260 if you want. It does seem easier to do it with the creedmoors now.
 
Back
Top Bottom