Talk to me about small rifle primer based 6mm cartridges...

[SSG Graybush]

So you're using it in a semi auto? I've never experienced feed issues with any cartridge, but my experience is limited. Are the rounds just oddly shaped such that the geometry get wonky? Steep shoulder angles and such?

No not a semi, a dbm chassis bolt rifle, but it could be any bolt gun. It has to do with the configuration of the mag, where the endented ribs are, when using short cases in mags initially designed for the 308. If the nose can hit the front of the mag it will sometimes drive. Save yourself the aggravation and pay the 100 bucks for the AI mag.

 

[DTubb]

So when the 6XC was designed the intent was to shoot long heavy bullets (115 gr 6mm's) out of a 2.850" magazine box..
All Creedmoor cases are .050" longer than the 6XC so the (6 & 6.5 long heavy bullets) need a longer magazine box.
How do you set the parameters for this?
You always seat the full diameter at the bullets base in front of the neck shoulder junction. This way the user attains maximum accuracy potential.
IMO a CM design flaw but what do I know..
Dtubb

 

[SSG Graybush]

So when the 6XC was designed the intent was to shoot long heavy bullets (115 gr 6mm's) out of a 2.850" magazine box..
All Creedmoor cases are .050" longer than the 6XC so the (6 & 6.5 long heavy bullets) need a longer magazine box.
How do you set the parameters for this?
You always seat the full diameter at the bullets base in front of the neck shoulder junction. This way the user attains maximum accuracy potential.
IMO a CM design flaw but what do I know..
Dtubb

None of you are making this decision any easier btw... It's driving me to drink.

See that's why you should do a 6XC. Where else do find a cartridge designer chime in. Help is a dm away. Plus its a great cartridge.

 

[Reemty J]

Judging by tons of wins and records, Mr. Tubb, I figure you forgot more than most of us know!! I rebarreled a 22-250 to a 6XC and it was a great thing for me. At the moment I am shooting Hornady 110 Atips and at a 100 yards I can put 3 shots in one ragged hole. Great cartridge design, my opinion. Thank you David Tubb!

 

[rickiesrevenge]

Be different! 6mm Long Dasher. Its the 6.5x47L with a dasher shoulder and neck. The one 6mm I struggled with was the 6x47L. If you get to looking around it seems like about 1/2 the guys struggle to get acceptable consistent accuracy. For hunting I'd do a creed

 

[StumpyJohnson]

No not a semi, a dbm chassis bolt rifle, but it could be any bolt gun. It has to do with the configuration of the mag, where the endented ribs are, when using short cases in mags initially designed for the 308. If the nose can hit the front of the mag it will sometimes drive. Save yourself the aggravation and pay the 100 bucks for the AI mag

So when the 6XC was designed the intent was to shoot long heavy bullets (115 gr 6mm's) out of a 2.850" magazine box..
All Creedmoor cases are .050" longer than the 6XC so the (6 & 6.5 long heavy bullets) need a longer magazine box.
How do you set the parameters for this?
You always seat the full diameter at the bullets base in front of the neck shoulder junction. This way the user attains maximum accuracy potential.
IMO a CM design flaw but what do I know..
Dtubb

This I agree with this, I calc from the ogive back to the base and then ensure the bullet seats like you describe. Which is why I want/hope/feel a long action is at least a viable option for a few of these cases. Am I totally wrong? I know freebore becomes the limiting factor but that can be addressed in chambering. I mean, a long action starts at the 2.8ish mark right? The ONLY reason I'm considering creedmoor is the thought that it'll feed well in a LA. I want to transform the Zeus action I have to shoot a 6mm cartridge that's efficient with powder, uses a SRP (availability reasons), bangs steel out to 1k and takes small/medium game to 300. Tell me why those expectations CANT be shouldered by the 6xc sir.

 

[DTubb]

This I agree with this, I calc from the ogive back to the base and then ensure the bullet seats like you describe. Which is why I want/hope/feel a long action is at least a viable option for a few of these cases. Am I totally wrong? I know freebore becomes the limiting factor but that can be addressed in chambering. I mean, a long action starts at the 2.8ish mark right? The ONLY reason I'm considering creedmoor is the thought that it'll feed well in a LA. I want to transform the Zeus action I have to shoot a 6mm cartridge that's efficient with powder, uses a SRP (availability reasons), bangs steel out to 1k and takes small/medium game to 300. Tell me why those expectations CANT be shouldered by the 6xc sir.

FYI- One of the 6XC other design parameters was the same linear body taper as a 308.
All CM's have less body taper than a 308.

If you are hung with a long action then all the design parameters surrounding a 6XC become moot. However all cases shorter than the 6x47 will have issues feeding as recoil will likely stagger your rounds in a loaded mag box.

 

[Justice1327]

This I agree with this, I calc from the ogive back to the base and then ensure the bullet seats like you describe. Which is why I want/hope/feel a long action is at least a viable option for a few of these cases. Am I totally wrong? I know freebore becomes the limiting factor but that can be addressed in chambering. I mean, a long action starts at the 2.8ish mark right? The ONLY reason I'm considering creedmoor is the thought that it'll feed well in a LA. I want to transform the Zeus action I have to shoot a 6mm cartridge that's efficient with powder, uses a SRP (availability reasons), bangs steel out to 1k and takes small/medium game to 300. Tell me why those expectations CANT be shouldered by the 6xc sir.

243 AI. Dies are available, They have SRP brass, you can set the bullets the way you like and if you use slow burning powder you can have longer barrel life, and easily use your LA .

 

[SSG Graybush]

This I agree with this, I calc from the ogive back to the base and then ensure the bullet seats like you describe. Which is why I want/hope/feel a long action is at least a viable option for a few of these cases. Am I totally wrong? I know freebore becomes the limiting factor but that can be addressed in chambering. I mean, a long action starts at the 2.8ish mark right? The ONLY reason I'm considering creedmoor is the thought that it'll feed well in a LA. I want to transform the Zeus action I have to shoot a 6mm cartridge that's efficient with powder, uses a SRP (availability reasons), bangs steel out to 1k and takes small/medium game to 300. Tell me why those expectations CANT be shouldered by the 6xc sir.

You don't need a LA. My Criterion barrel is throated at 105 thou, I believe. I think that's saami standard, idk. Ask Mr. Tubbs that question. And the guy at NSS knows all the specs as well, thats where I got my remage barrel. I don't think you need more free bore then that. My barrel liked 37 thou jump and the node was 5 thou across.
Mr. Tubbs has it dailed in, I did a ton of load development and ended up back at his recommend 39.5 grs of H4350. He recommends that with the 115 gr dtac. There were none available at the time so I tried 112 match burners, which had the highest bc of the 6mm bullets at the time. That charge still was the best. I don't know what my coal is(I only measure cbto), but it easily runs well in a standard SA.

 

[SSG Graybush]

243 AI. Dies are available, They have SRP brass, you can set the bullets the way you like and if you use slow burning powder you can have longer barrel life, and easily use your LA .

This would give you(OP) the most case capacity, and out run a 6 CM. And not go sub sonic till after 1 mile with a max load.
H1000, compressed. That was a old school recipe comp shooters used with a 243 win, before all the newer 6's came out. If you were gonna shoot 1000+ yards all the time this would make sense.
But 1000 and in the 6XC will get it done, and with less powder. This is my 6XC dope. Check out the numbers, it carries over 1200 #'s of energy to over 500 yards. Even with a lower bc hunting bullet 500 yards would be doable, for deer. But there's a 115 gr and 107 or 108 Berger hunting bullets with only a slight less bc so, the numbers could be very close. Environment is 1000 ft alt, 59 °, av baro, 50 rh. But in a long action, Id look at those Badland bullets. Definitely. They probably have a even higher bc solid.
And if you run out of H4350, Mr. Tubbs has a H4831sc recipe as well. Never used it but am pretty sure it's not bad, just a tad bit slower then H4350.

 

[Damage Inc.]

If you're going to hunt with it, I'd stay LRP. I had all kinds of issues hunting with a 6.5x47 in sub-20 degree weather. I tried a couple different SRPs, and a couple powders…. but if it was cold, I'd have hang-fires and random fliers frequently.

Anyone else have issues in cold weather with SRPs and powder charges in the 40-45 grain range?

 

[SSG Graybush]

If you're going to hunt with it, I'd stay LRP. I had all kinds of issues hunting with a 6.5x47 in sub-20 degree weather. I tried a couple different SRPs, and a couple powders…. but if it was cold, I'd have hang-fires and random fliers frequently.

Anyone else have issues in cold weather with SRPs and powder charges in the 40-45 grain range?

Did you try a mag primer? I haven't tried my 6XC in temps under 40° so I don't know. Maybe Mr. Tubbs will enlighten us. But that's a good question.

 

[StumpyJohnson]

I think the only question is one of feeding which I'm still not certain of, I understand that all my other design constraints for the cartridge kinda go out the window when utilizing a long action. But its what I have and what I'd like to use. The tikka seems the most sensible format because I can swap the bolt stop and magazine and (I'd imagine) be fine. BUT, finding an extra tikka bolt with the proper sized face is the difficulty. The Zeus is easier to find the parts for, but the question is whether the hawkins hunter dbm, using a la standard mag, will feed effectively. Seems to me that it should, but what do I know.

What I do know is that I'm definitely a "F%*$ around and find out" type of guy. And I bet with few chunks of delrin and a dremel I could probably fab up some sort of spacer.

 

[StumpyJohnson]

WHelp...



That clinches it. 6xc in a terminus zeus long action...