I'm thinking 1:10, expecting to use standard cup and core through about 80 gr. Sound right?
How about length? I'm thinking 22" sporterweight bbl?
Sycamore
A 10 twist will definitely stabilize standard cup and core bullets to 80 grains. I verified that with 2 bullet makers (Hornady and another I forget). I had mine done at 1:9 so I could shoot Barnes and 100 c&c. 22" sporter weight would be a nice length and weight. I built mine on a Sako 461 so had the barrel done to that contour and length. The gunsmith finished it at 24 but with the short action length the barrel doesn't seem long. It's a great cartridge, I'm sure you'll love it when it's finished.
Frank
I've got a 9" on mine at 21" long...
Don't worry about 'over' twisting too fast, never had a problem with too fast a twist. A 9 will compensate for reduced speeds vs. a 243/6mm Rem. 21-22 is great, mine was a 21" 12 twist and it would max out at 85 BTHP for hunting accuracy which was the most bullet I planned to shoot, yet it preferred 70s much more, just as my first 6mmBR did, also a 12 ROT.
A 9 sound great, as even if you did an 8", not likely your case capacity will drive 105 VLDs or heavier fast enough when seated down in the case to make them viable.
55-85s is where I'd spend my time with a 45 or 6TCU, and H335 is a good place to start w/good brass (mine preferred Win/commercial vs. Mil-Surp).
Let us know how it shoots.
I just sent one out to become a 6mm/223 and went 1-8" twist. Don't be skeered of twist. Unless your building a BR rifle to shoot a specific weight/length bullet I'd always add a little twist.
A little extra twist is far better than being a hair short.
I had a 14" twist barrel on my 6X47 at 20" on a heavy barrel (to make weight), and I shot mostly hand-made bullets in the 60 to 70 gr range. The thought in those days was slower twist was more accurate (benchrest terms)
In a sporter 10" twist would probably work well. It works well enough in my .243 and 6mm rifles. The "magic barrel length" from the Warehouse is 21.75".
jim
10 twist, you can shoot the heavies and you sure can't over spin the lighter bullets. I know, I have owned one on a AR15 platform.
I couldn't pay me to run a 1-10" twist
I couldn't pay me to run a 1-10" twist
Is there a particular bullet you're planning on loading, that accuracy would be hurt by 1:10 ?
Sycamore
Anyone neck up nickeled 223 brass for 6x45? Easy way to keep the cases separated? Or more trouble than it's worth?
Sycamore
I have and it necked up fine, though I have a general dislike for nickle.
My 6mm/223 arrived yesterday from the smith.
I had a 14" twist barrel on my 6X47 at 20" on a heavy barrel (to make weight), and I shot mostly hand-made bullets in the 60 to 70 gr range. The thought in those days was slower twist was more accurate (benchrest terms)
jim
Ditto.
I had the same chambering in the early 1970's for benchrest competition, a 6x47 w/a 1-14" twist and shot the best bullets I could find in the 68-70 gn weight. IIRC, I used 748, or 748BR powder, with Rem 7 1/2 primers.
Don
Hmmmm.....
6x45, or 6mm-204....
80 grain TTSX....
Hmmm.....
That bullet was accurate out of my 6x but it wasn't very fast...
It would be a 300 yard bullet in that cartridge before it dropped down below optimal performance velocity in my rig...
6x45 or 6mm-204? Define "not very fast", if you can, please.
6x45...
I could only get that bullet to 2730 in my 21"er with the powder that gave me the highest velocity across the board: H335.
Having a hard time seeing where the 6x45 or maybe even the 6mm-204 would whoop on the .223AI and 75 A-Max combo, then.
I'm not sure who said it would...
Keep in mind the above numbers are a sample of one...
Understood completely, just an observation.
For a light, handy little walking around rifle, I think the .22" to .25"s on the .223 and .204 cases make a lot of sense.
Yessir...
The exact reason I built mine...
Cannot wait for GS Customs to start making bullets on US soil. Their 75 gr. HV would be an interesting one to run in the 6x for a do all...
I couldn't pay me to run a 1-10" twist
Is there a particular bullet you're planning on loading, that accuracy would be hurt by 1:10 ?
Sycamore
Is there one you plan on using that wouldn't work in a 1-8" twist? I'd not bank on the TSX working, or Swift or 95gr Ballistic tip in a 1-10" or not well.
Besides goo factor increase greatly with rotation.
just got in a bunch of 55 gr 6mm, so I'll be shooting quite a few of those, I expect.
I was thinking that the small case would mean that the larger (longer) bullets would be too slow for much, anyway.
Sycamore
Ok, but if I have a 1990 pound boat I don't buy something that has a max towing capacity of 2000 pounds. Your mileage obviously varies, good luck.
Well, if all the cool kids are doing 1:8, maybe I'll go 1:9
Sycamore