What are all the different 6mm short action calibers?

[_Raining]

I am considering switching from 6.5 creedmoor to a 6mm but I am much less informed about the 6's than I am 6.5. I am NOT asking anyone to put together info on the cartridges (Barrel life, brass availability, feeding, load dev, reamers, MV, dies etc), I can do the research myself... right now I am just looking for you to help me put together a list of all the 6's that use a 308 bolt face so I can start researching them.

So far I have:
6 BR
6 XC
6 SLR
6 Dasher
6x47 lapua
6 creedmoor
243 win
243 AI
6 BRX

Let me know what I am missing.

-Thanks-

 

[leftyk82]

6 PPC
6 BR Ackley

 

[just browsing]

Think you’ve got the main ones, though you may also check out the 6 BRA.


You won’t find any info on it here but I am shooting a 6mm Comet designed by Isaiah Curtis. 6BR case blown out to 40 degree shoulder - essentially a ‘Dasher Improved.’ Just gets 105 range bullets to the mid 3s without destroying brass.

 

[Midwestside]

6mm Remington
6mm Competition Match

 

[bohem]

Think you’ve got the main ones, though you may also check out the 6 BRA.


You won’t find any info on it here but I am shooting a 6mm Comet designed by Isaiah Curtis. 6BR case blown out to 40 degree shoulder - essentially a ‘Dasher Improved.’ Just gets 105 range bullets to the mid 3s without destroying brass.

How is that a 6 Dasher improved? Did he shorten the neck? The Dasher is already 40 degree shoulder and pretty near straight walled already. It's so short in the neck that guys who've copied the Dasher neck and shoulder into bigger cases, like 6mm Creedmoor, have noted a lot of difficulty with seating depth issues because the inertial loading on the bullets during recoil changes the seating depth... it's about as "blown out" as a 6 BR gets...

 

[ThePretzel]

How is that a 6 Dasher improved? Did he shorten the neck? The Dasher is already 40 degree shoulder and pretty near straight walled already. It's so short in the neck that guys who've copied the Dasher neck and shoulder into bigger cases, like 6mm Creedmoor, have noted a lot of difficulty with seating depth issues because the inertial loading on the bullets during recoil changes the seating depth... it's about as "blown out" as a 6 BR gets...

What he's describing makes it sound like it's no different than 6BRA, unless the neck is getting moved. Could be entirely wrong on that, but if all he does is change the shoulder angle I'm pretty sure it's just BRA.

As far as other calibers in 6mm, here's a few more:
.243 Win-Match
.243 AI-Match
6mm Creedmoor Match
.243 WSSM
6x45mm (.223 case necked out)

 

[jducos]

6x284

 

[steve123]

6 PPC
6 BR Ackley

6PPC uses a smaller diameter bolt face which is the same as 7.62 x39 and 6.5 Grendel and is .443" vs the normal .470".

243 WSSM uses a .540" or mag bolt face.

 

[ThePretzel]

6PPC uses a smaller diameter bolt face which is the same as 7.62 x39 and 6.5 Grendel and is .443" vs the normal .470".

243 WSSM uses a .540" or mag bolt face.

Whoops, didn't see that he wanted things specifically on the 308 bolt face. That would disqualify 6x45mm as well, since it uses a .384" bolt face the same as .223 Rem.

 

[trophyhunter]

What about the 6SIP
From what gather is a 6creed with 40* shoulder and probably less taper

6creed-Dasher

 

[jakelly]

Crusader
6mm AI

 

[dannySH]

Hey! Let's debate which one is better!

Please don't do this!!!

 

[lash]

What he's describing makes it sound like it's no different than 6BRA, unless the neck is getting moved. Could be entirely wrong on that, but if all he does is change the shoulder angle I'm pretty sure it's just BRA.
....

That was exactly my first thought.

 

[steve123]

Hey! Let's debate which one is better!

I wonder how many guys are running a BR based case with 105's for matches that suite and also run a big case with 115's going almost 3200 for matches in heavy winds and longer distances???

 

[Sledge1]

6 WOA
6 DTI
6 X 6.8

 

[sandwarrior]

6x284

6-.284 = Frickin' Laazer

 

[steve123]

Not me. I run my 115s at 3000fps.

Yeah I guess 3200 fps is more 6mm Crusader territory.

3000 fps is what I used to run in my 6x47L with DTACS and had the most success with when I was at my peak. My friends give me a hard time and tell me I'm past my peak which is true, lol.

 

[sandwarrior]

I was going to suggest 6 SAUM....Freekin Layzzeeir!

Ha Ha, as you probably know though, anytime you get into "freekin lazer' territory, you get into REALLY SHORT BARREL LIFE territory too!...

 

[Dai Bando]

Hey! Let's debate which one is better!

6 Dasher is by far the greatest 6mm for the kind of shooting we do.

Talk amongst yourselves, I'm all veklempt....

 

[flyer]

Looking at the barrel life of 6mm cartridges designed to fit in a .308 magazine, they seem to be pretty overbore.

Too much case capacity for too little MV means a not particularly efficient cartridge.

I was looking at .224 Valkyrie for an AR and thought the same thing, not very efficient but I found a 6mm Valkyrie wildcat which really means a 6.8 SPC wildcat called TAC 6 which will shoot a 105 grain bullet at 2,800 fps from an 18" barrel.

No rifling twist issues, fits fine in 6.8 SPC magazines, feeds fine, more bullet, more MV, almost as much BC.

Maybe that would be enough to make a switch to AR15?

 

[sandwarrior]

Looking at the barrel life of 6mm cartridges designed to fit in a .308 magazine, they seem to be pretty overbore.

Too much case capacity for too little MV means a not particularly efficient cartridge.

I was looking at .224 Valkyrie for an AR and thought the same thing, not very efficient but I found a 6mm Valkyrie wildcat which really means a 6.8 SPC wildcat called TAC 6 which will shoot a 105 grain bullet at 2,800 fps from an 18" barrel.

No rifling twist issues, fits fine in 6.8 SPC magazines, feeds fine, more bullet, more MV, almost as much BC.

Maybe that would be enough to make a switch to AR15?

I'm not following you. Rifle twist issues are a case of what you want the rifle twist to be to shoot the bullets you want.

The .243 is overbore if you shoot it too fast. Otherwise, it's about the edge of overbore or not in controlled shooting volume. 6mm Remmy is s step up. The 6mm Creed is right below it. That's why the 6BR, Dasher, BRX, 6XC all REALLY shine. And, no, a 6mm TAC (or other variant) is not going to give you the velocity of the .308 based cases. Which all of the above are.

As far as bolt guns, it's much easier to get a system that takes some kind of .308 magazine than a 6.8 magazine. Dasher, BRX and 6XC again, really shine as they fit well in these mags. But, yeah a 6.8 magazine system can be made if you hunt for parts long enough.

 

[flyer]

.224 Valkyrie is the one with rifling twist issues.

I never said it would hit the velocity of .308 case size 6mm chamberings, it's just less overbore than they are and less overbore than .224 Valkyrie.

I also said it fits nicely in an AR with 6.8 SPC magazines. That's opposed to some of the .473 case head 6mm chamberings that can have issues in a .308 size magazine.

At the very least it's a good point of reference to show what happens when case capacity goes down to that level.

 

[sandwarrior]

.224 Valkyrie is the one with rifling twist issues.

I never said it would hit the velocity of .308 case size 6mm chamberings, it's just less overbore than they are and less overbore than .224 Valkyrie.

I also said it fits nicely in an AR with 6.8 SPC magazines. That's opposed to some of the .473 case head 6mm chamberings that can have issues in a .308 size magazine.

At the very least it's a good point of reference to show what happens when case capacity goes down to that level.

Again, I'm not fully following you. The .224 Valkyrie should have a 1-7" twist. That will launch a "new" 90 gr. SMK/TMK at 2700+ fps. I've seen a number now, with longer barrels, right under 2800. That will give pretty nice results out to 1k and will hit even to one mile. Lightweight bullet overall would be the drawback.

I was pointing out the Dasher, BRX, and 6mmXC all do well in standard .308 mags. For a bolt gun, this is the way I'd go. However, your position of it being usable also in an AR is a valid point. Having matching bolt and AR rifles would be sweet. As the above mentioned cases are too powerful to really be chambered in an AR-15 platform. Many have tried doing even just the BR and it breaks bolts eventually. The 6 TAC or Hagar or whichever variant isn't bad about breaking bolts.

That's a good idea, but the OP was interested in a .308 case head. He might already own a rifle he intends to use for it? I think the same of the PPC and Grendel cases. Good idea in a lightweight bolt gun, but not the question today. A good point though.