Do fast twist 243's make the 6mm Creedmoor pointless?

[Q_Sertorius]

But with companies like Tikka now offering faster twist barrels, maybe we should expect to see offerings from major ammo makers.

Yes, we should. I am about to spend the afternoon shooting a variety of .223 factory ammo from 55-77 grains. Not all of it will shoot optimally in my 1:10 twist barrel, but that doesn’t stop manufacturers from selling it. Why should factory .243 or .270 be any different?

 

[The Guide]

But with companies like Tikka now offering faster twist barrels, maybe we should expect to see offerings from major ammo makers.

No. They cannot without going against SAAMI approval. There is a reason why it takes so long to get a cartridge to market and being SAAMI approved. You may see something from overseas but they generally follow CIP regulations which is also based on a 10 twist barrel. Liability is the name of the game. Ammunition manufacturers already carry great liabilities and to change products against the approval of the industry standard would put them at a greater chance of being found liability for something.

Jay

 

[nm.otter]

You should be able to rechamber a factory .243 into 6mm Creedmoor.

 

[HandgunHTR]

Another variable that a lot of you are overlooking is that in order to get the performance out of heavy bullet in a .243 casing, the bullet has to be seated out pretty long so as not to intrude on the powder column. Loading it long means that most factory .243 throating and magazine setups won't work when seating the bullets out where they need to be. I know at least two guys that have 8-twist .243 Tikkas that are using either M+ or LA mags in order to get the 108/109s out to where they need to be on their firearms. It is pretty easy with Tikkas which are notorious for long throats and the bolt stops and mags can be swapped very easily. Not so with most other factory firearms.

As an example of what I am talking about, compare the picture below to the one that Taper Pin posted. Mine is the pic off of the Unknown Munitions website of a 6mm Creed loaded with the same 105 Bergers. Notice how much more bullet is outside the cartridge.

 

[The Guide]

Yes, we should. I am about to spend the afternoon shooting a variety of .223 factory ammo from 55-77 grains. Not all of it will shoot optimally in my 1:10 twist barrel, but that doesn’t stop manufacturers from selling it. Why should factory .243 or .270 be any different?

Since 223 and 5.56 ammo can be used fairly interchangeable and 5.56 NATO is specified as a 7 twist, 223 and 5.56 ammo run heavier weights than other common cartridges do. Hornady 223 match heavy rounds (I think they were 77gr BTHP) had a twist requirement printed on the box but my local gun store quit stocking them since people kept trying to bring them back when they would keyhole at 50 yards in some rifles. I can see that happening with other cartridges if they supply heavy for caliber bullets for fast twist barrels.

Jay

 

[Tod osier]

Another variable that a lot of you are overlooking is that in order to get the performance out of heavy bullet in a .243 casing, the bullet has to be seated out pretty long so as not to intrude on the powder column. Loading it long means that most factory .243 throating and magazine setups won't work when seating the bullets out where they need to be. I know at least two guys that have 8-twist .243 Tikkas that are using either M+ or LA mags in order to get the 108/109s out to where they need to be on their firearms. It is pretty easy with Tikkas which are notorious for long throats and the bolt stops and mags can be swapped very easily. Not so with most other factory firearms.

As an example of what I am talking about, compare the picture below to the one that Taper Pin posted. Mine is the pic off of the Unknown Munitions website of a 6mm Creed loaded with the same 105 Bergers. Notice how much more bullet is outside the cartridge.

View attachment 935292

Yes and with long bullets, especially copper, you lose capacity and velocity. They are neck in neck, but at the top end of the bullet length (reducing capacity) the 243 falls off.

 

[satchamo]

I don’t think so, but I would almost certainly get a fast twist .243 before I got a 6mm Creed. But that is because I own one .243 already. I haven’t tested whether a 1:8 twist .243 can get good accuracy out of the heaviest/longest factory ammo.

It can. I run a 243 with 108s and 2.8 OAL and that gun is more accurate than me. And I get very good velocity out of 18” - 2900 and I’m not beating up my brass.

I’m running aics mags in an Xlr element but I think the stock tikka mags would allow the same seating depth.

 

[satchamo]

Another variable that a lot of you are overlooking is that in order to get the performance out of heavy bullet in a .243 casing, the bullet has to be seated out pretty long so as not to intrude on the powder column. Loading it long means that most factory .243 throating and magazine setups won't work when seating the bullets out where they need to be. I know at least two guys that have 8-twist .243 Tikkas that are using either M+ or LA mags in order to get the 108/109s out to where they need to be on their firearms. It is pretty easy with Tikkas which are notorious for long throats and the bolt stops and mags can be swapped very easily. Not so with most other factory firearms.

As an example of what I am talking about, compare the picture below to the one that Taper Pin posted. Mine is the pic off of the Unknown Munitions website of a 6mm Creed loaded with the same 105 Bergers. Notice how much more bullet is outside the cartridge.

View attachment 935292

My tikka is throated longer than I can even load. I don’t have my notes in front of me but it’s over 2.8 before I was hitting lands with 108s. But I have heard of folks getting shorter throats on the tikka 1:8s.

 

[Macintosh]

6cm just makes a handful of incremental changes to make it “long range optimized” without needing to reload or deal with mag length, etc. Tikka doesnt have a 6cm rifle yet, so offering a faster twist 243 is one way they can address some of those same customers, without any down-side. That’s different from a major ammo manufacturer offering a product where many (most?) customers wont read the fine print and may have a bad experience. So no, as other said I dont think it makes the 6cm any less relevant…most people DONT reload.
The fact that some people dismiss or are even hostile to newer cartridges that make incremental changes for a specific purpose available off the shelf, is really strange to me though. It aint hurting anyone, and its helping some.

 

[PathFinder]

My current Tikka 243 Improved is on a factory threaded 20" Tikka barrel that I reamed with a drill and rented reamer. The throat was a bit shallow for the 115 DTAC, so I cut it .075" deeper.
It's able to do close to 3100 with H1000. That showed an ejector mark in Alpha brass, so probably pretty hot. The plan is to back it off to 2900 for quick drop. The standard 243 is probably capable of that. My guess is that the 6 Creedmoor probably is too, but would require a hotter powder. I'm planning to try that on a Kimber 84M next year.
The two reasons that I went the 243 Improved route were the ability to utilize H1000 in hopes of better barrel life, and that was the only off the shelf option at the time. Were I starting again right now, I'd just snag an LS Wild 6 Creedmoor barrel.

Sent from my Pixel 6 using Tapatalk

 

[Hnthrdr]

But with companies like Tikka now offering faster twist barrels, maybe we should expect to see offerings from major ammo makers.

I hope so! Or tikka could just offer a 6cm rifle…

 

[bnsafe]

so what im hearing is no reason to buy a 1 8 twist 243 if you dont roll our own. just buy a 10 twist an move on

 

[nm.otter]

If you have a choice, buy the 1:8" - more options later, and (as time goes on) likely better resale value.

 

[Q_Sertorius]

so what im hearing is no reason to buy a 1 8 twist 243 if you dont roll our own. just buy a 10 twist an move on

I haven’t heard any reason not to buy a 1:8” twist Tikka .243. It will still shoot the heaviest/longest factory loads. But it won’t be limited if you want to reload for heavier/longer custom loads (e.g., 115-).

 

[bnsafe]

does it spin the 90 grain stuff to fast. not trying to hijack the thread, sorry

 

[Ajsomp]

I have the factory 20” threaded 243. I’m going to shoot loaded 95TMKs this year until I swap it out with a 6 creed. If you’re never shooting over 400 you can still kill with factory 243 but you’re losing out on the fast twist benefit.

 

[vonb]

I’d buy the faster twist .243 all day long unless I’m wanting to shoot light bullets. That’s if I’m shooting factory ammo.


Having both a 6 creed and .243, I find the .243 feeds better due to the case taper and shoulder. Not that the 6 creed feeds poorly. Also, the 6 creed seems to have a wider node than the .243 if hand loading. The 6 creed is rated at higher SAAMI pressure than the .243. That’s why you see higher factory printed velocity for the creed than the .243.

 

[nm.otter]

MV * 720 / twist = RPM
1:8 twist hits 300k RPM at 3,333 FPS
58gr V-Max could be an issue (thin jacket, 353k RPM).