6mm creed vs 243?

O

Oakhill

Member
Thinking about a new ar10 upper. 20" for suppressor and 1-12 twist to get 55's as fast as possible. Is there any advantage with the 6 cm over a 243? Not much info out there about 55's with the right twist but I have read a few where guys say its faster than 243.

Is there anyone on here shooting 6 creedmoor 55gr in a 1-12?
What barrel length do you have and what speeds are you getting?
Any feeding issues in ar10 with the short bullets?
Thanks
 
If it's an AR10, I'd go creedmoor for the better fit in the mag and OAL. If it was a bolt, I'd go .243 for easier available brass.
 
I have both and prefer the .243 as it shoots everything from 58-103 grainers well. 6 creed is picky and if I want under MOA (1/2 consistently), than it likes the 70s's best, but will shoot 58 grainers around 1.5" at 100 yds.

I also have them in bolt action which I prefer 90% of the time when calling suppressed. I hunt pipeline and wooded areas and usually only get one shot anyway, but if I hunt open areas where I have an opportunity for doubles than AR 10 goes.
 
If you want as much speed as possible, get a 243AI. But it wouldn’t be my choice.

I’m 11 barrels deep in 6 creed (after shooting 243win and AI for many years and a couple dozen barrels before 6 creed), and certainly haven’t found 6 creed to be picky.
 
Wow, thats a lot of shooting. I have been shooting 243 for years and have lots of brass but a lot of it is getting old. I thought a new barrel would be a good time to start fresh with new brass so could easily switch to creedmoor.
I have a 700 243 with a 26" 1-12 that shoots 55's to 4000+ easily. My ar10 20" 1-10 only shoots them 3575. I was wondering if the 6 creed case design was "more efficient" or something that it would work better in a short barrel. I just cant seem to find any real load data on 6 creed 55gr with a slow twist to compare to.
 
The 6 creed doesn’t give up as much as it could, but loaded to the same pressure, it can’t keep up with the 243win. It’s a smaller case. No voodoo - there’s just no replacement for displacement.

But I also think 4,000 is just a number. Giving up 100fps, what really changes? Barrel length will be your bigger knob - add 2” to a 6 creed and it catches a 243win. But going smaller case and shorter barrel will only cost you speed. No doubt.
 
I run a 22 Creed with an 18" Xcaliber 10 twist and a Varminter 3.0 Suppressor. With 60TMK I get right at 3650, I can get little over 3800 with 55gr BT's, both loads I am using 4064. I have a lot of that on hand. I think I could do better with Varget but this has worked well and coyotes can't seem to tell the difference. I can tell you out of 50 or so coyotes those 60 TMK's are the ticket. From 50yds out to 350yds if the shot placement is good there is little to no fur damage and it hits like a hammer. Even with an off shot I really haven't tore to much up.
 
Thats really impressive for an 18" barrel. Sounds a lot like 6mm 55 nbt, very little fur damage and knocks them down hard. I have considered a 22 creed also I just thought a 6mm would beat it on the same length barrel.
This is for night hunting with no rangefinder so going for as flat as possible to 300-400 yds.

I found new load data online from sierra and nosler. On 55 gr loads from a 24" barrel nosler has the 6mm creedmoor beating the 243 by a good 100 even up to 200 fps. Most of the loads for the cm are over 4000 and very few for the 243 are. Lots of big numbers for 24" barrels. The "most accurate powder tested" in 6 cm was cfe223, 46.5 grs max at 4077 fps! The "most accurate" in 243 was h414, 49gr max at 3870 fps. Whats going on here? Is this from the powders they use that work better in the cm? Or maybe trying to sell more creedmoor rifles?
 
If you go the 6 or 243, make sure that the freebore matches the bullet length you want to use.

I have shot half a dozen custom 243 Win with either zero or .020 freebore and they shoot tiny, tiny groups with bullet weights from 55-80g. Now if you have a barrel set up to shoot 105's, then those light loads will be picky to get to shoot, if they will shoot well at all....especially the 55's.

Remember that the SAAMI pressure set up for the different cartridges, and I don't know what they are for each of these. The 243 Win does have semi auto's made by Browning and Rem, so I would expect that posted pressures for the 243 to be Less than the Creed.

The 22 & 6 creed have the approximate capacity as a 6-22/250 AI....for what ever that is worth.
 
6 creed is available in semiautos as well.

243win SAAMI standard is 60kpsi, 6 creed is 62kpsi. The difference is moot - no reason 243win can’t be loaded to 62kpsi either though, same bolt face, same actions, same barrels… same pressure capability.
 
…just zero your .243 at 275 and shoot 70-90 grainers to kill them vs “knocking them down” out to “400 yards”….or just call them in to under 200 yards.
There’s better options than a 4000 fps 55g 6mm bullet….
 
Originally Posted By: limbhanger10…just zero your .243 at 275 and shoot 70-90 grainers to kill them vs “knocking them down” out to “400 yards”….or just call them in to under 200 yards.
There’s better options than a 4000 fps 55g 6mm bullet….

Word.
 
Originally Posted By: OakhillThinking about a new ar10 upper. 20" for suppressor and 1-12 twist to get 55's as fast as possible. Is there any advantage with the 6 cm over a 243? Not much info out there about 55's with the right twist but I have read a few where guys say its faster than 243.

Is there anyone on here shooting 6 creedmoor 55gr in a 1-12?
What barrel length do you have and what speeds are you getting?
Any feeding issues in ar10 with the short bullets?
Thanks



Going through the same process myself and IMO 243, all day long. Not that I'm anti 6creed because its great for what it was designed for which is a long throat to accommodate long, heavy, high BC bullets and a fast twist barrel.

Unless you have your own custom 6 creed reamer and a slow twist barrel, it won't be anywhere near optimal for light bullets and probably minimal if any factory ammo with 55s or 58s for the 6 creed.
A great example is guys running 6ARCs are struggling to get factory offerings to shoot the light 55s and 58s well, they was designed exactly like the 6 creed for long high bc bullets causing a mile of jump for light bullets.

The sammi spec 243 chamber is based on lighter weight bullets because thats what they mostly had in 1955 when it hit the shelves. TONS of factory ammo with light, medium and heavy bullets, more case capacity along with more components makes it a no brainer.
 
I agree with Kino on this for sure. In my case I knew I wanted to run mine on an AR10 platform and thought the creed would have less cycling issues. I called XCaliber and explained what I wanted to run and that's how I came up with the 1-10 twist, I know I can touch the lands and still load to magazine length, I am not sure if they have different reamers for different twist rates but I do know this gun shoots as good as my ability can.

Guys I hunt with both have 6 creeds - one shoots 65 grain Vmax and has the same results as me. The other shoots 70 grain Varmegeddon's, his 70's are a bit more destructive.

Everybody has different ideas of what they want but personnaly I like my 60's to leave all the energy in the coyote. I load for accuracy first then speed, but mine is a dedicated night gun so I did want as flat of trajectory as I could get. I have really liked mine and have no complaints.
 
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riverhunter55 said:
I agree with Kino on this for sure. In my case I knew I wanted to run mine on an AR10 platform and thought the creed would have less cycling issues. I called XCaliber and explained what I wanted to run and that's how I came up with the 1-10 twist, I know I can touch the lands and still load to magazine length, I am not sure if they have different reamers for different twist rates but I do know this gun shoots as good as my ability can.

Guys I hunt with both have 6 creeds - one shoots 65 grain Vmax and has the same results as me. The other shoots 70 grain Varmegeddon's, his 70's are a bit more destructive.

Everybody has different ideas of what they want but personnaly I like my 60's to leave all the energy in the coyote. I load for accuracy first then speed, but mine is a dedicated night gun so I did want as flat of trajectory as I could get. I have really liked mine and have no complaints.
Click to expand...
What bullet and powder are you running?
 
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