6mm advice wanted

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by jacack, Oct 2, 2010.

  1. jacack

    jacack Well-Known Member

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    I am going to build a 6 but there are too many choices, I plan to hunt deer and goats out to 500 if conditions are right and shoot some targets with it. I want it to feed decent from a magazine and be around 10-12lbs with optics. I have looked at the 6X47, 243, 243ai, 6xc. but i am having a hard time choosing, i want the best barrel life but would want to shoot 105-107 and possible the 115s

    please let me know what you have and why
    thank
    jared
     
  2. TMR

    TMR Well-Known Member

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    Jared,

    I have built and shoot all but the 6XC. Getting a 10-12lb rifle with optics isn't that hard in this caliber of rifle.

    Sendero Contour
    Short Action
    HS, Manners, or McMillan stock
    NF scope


    Here are the break downs in velocity

    6x47L
    105 Berger 3180-3300 26-30" barrel
    115 Dtac 3050-3100 (only tested in 26-28" barrel)

    243Win
    105 Berger 3000-3150 26-28" barrel
    115 Dtac 3050-3100 26-28" barrel

    243AI
    105 Berger 3250-3350 26-28" barrel
    115 Dtac 3200-3290 26-28" barrel


    The 6x47L just takes running 6.5x47 Lapua brass into the 6x47 FL sizer, load and go shoot. Point of impact is the same. Extremely easy to load for and very accurate.

    243 Win is pretty straight foward. If setup correctly, is accurate as hell and easy to load for.

    243AI requires fireforming. With my 115 Dtac's and 105 Bergers, I run the same load in the virgin cases as I do in hot loads. I used to back down some, but I found that case life is the same and point of impact and velocity are almost identical. I also have a fireform barrel that I can make alot of cases in fast and that saves on barrel life. This is the caliber I use the most. I run 115's Dtacs at 3240 in a 27" barrel. Hits hard and fights the wind pretty well.


    Hope this helps. All of these would take deer out to 600 if the shooter can place the shot. I have shot deer and antelope out to 950 with the 243AI and had no problems at all.
     

  3. jacack

    jacack Well-Known Member

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    that does help, didnt think you could get that much out of the 243AI with 115s,

    I have a 700SA in a mcmillan that i was planning to use i have a box of 243 lapua brass so i was leaning that way, just its a 223wssm now so i will have to get a bolt from ptg i guess, what about twist for the 115s in the ackley, will a 1/8 work or will it need to be 1/7 and whos barrel, was thinking about trying a brux but havent ever used them

    thanks
     
  4. Long Time Long Ranger

    Long Time Long Ranger Well-Known Member

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    I have several of the big 6mm's. For your purpose considering extended barrel life I would go with the 243 AI. It is one of the most accurate rifles ever designed and will easily serve your purpose. The big 6mm's off the '06 case are faster by 200 fps but barrel life suffers with the target shooting. After all things are considered the 243 AI is one of my favorite rifles.
     
  5. Trickymissfit

    Trickymissfit Well-Known Member

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    I've been a 6mm nut for a long time. Started out like most did with a .243, and looked for greener pastures soon afterwards. I found that anything a .243 could do, the 6mm would do alittle better. The heavier the bullet the wider the gap. I've never owned a 6x47, so can't say much. But I do own a 6x250AI with a 1:8 twist barrel. It's not perfect, but still better than most would expect. I can hit 3000fps with 107 grain bullets, and hold .25" groups at 100 yards. On the otherhand the 6mmHLS is a better round than most anything else out there, and very easy to built a rifle on. The HLS would be my choice by a wide margine
    gary
     
  6. jacack

    jacack Well-Known Member

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    Never heard of that one, what's it based on?
     
  7. Gene

    Gene Well-Known Member

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    If you want to buy ammo over the counter go with the 6mmBR, and an 8 or 9 twist to handle the heavy bullets. Cooper can build one with your specs at a pretty reasonable price.

    If you stuff your own, any of those mentioned above are OK. I question 3200 fps with the 243 AI and 115 gr. bullets. I am shooting a 6 Dasher with 26" barrel, and 105 gr. Bergers, I can't get over 3100 fps.
     
  8. Trickymissfit

    Trickymissfit Well-Known Member

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    I rebuilt two Coopers, and I can tell that they use a lot of nice parts, but that's where it ends. I'd go the Remington route before even thinking about a Cooper. And I'm not exactly big on "big green" these days. Savage chambers a 6BR, and probably others as well. I have a Mod. 70 chambered in 6BR with a no turn neck. No comments on the gun itself as I probably have not began to get the barrel broke in let alone find the perfect loads. Mine is a 1:14 twist Masker barrel that is a strait 1.25" @ 22" long. Never intended to ever shoot anything much heavier than 80 grain bullets in it right from the start (I built it as a 350 yard dog gun). Out of the box the 6BR is my gun for sure, but the HLS does it all in spades. It's an easy chamber to cut, and dies are easy to do as well. It's really nothing but a 6mm Remington made short. Or very similar to a 6XC but with the 6mm neck and Ackley shoulders (in OTW's the same round I shoot but with a longer neck length.)
    I gotta agree with you in that I'd think a true safe load in the .243AI with 115 grain bullets is outta reach. You might get 3100 fps with 105's. And even then the neck length is not fun when looking at the full bullet range. A 3000 fps load in my 6/250AI took H1000 powder as well as Retumbo (I used that, but cannot confirm the velocity right here). On the otherhand the killingest round I ever own was a 6mm Remington. But never bothered with bullets heavier than 90 grains (it had the faster twist rate barrel). Using Berger 88's, it would shoot further than I had any business shooting. But out past 750 yards it was getting ragged due to velocity loss (a 6mmAI would have helped a bit, but a 1:8 twist barrel would have solved that problem).
    Recently I got on a jones to built my own big six, and a couple juniors in a switch barrel concept (actually a two bult gun as well). I came up with my own design, only to find it was within .015" at the shoulder of the HLS. Thus a waste of time! The second one is a 6BR, but with a 1.218" shoulder deminsion, and the over all length being adjusted. The third is a short range round that is ment to use 70 thru 80 grain bullets. It's basicly a 6/47 (the small case) made made into a 6/222AI but with a shoulder length of 1.36".

    gary
     
  9. Trickymissfit

    Trickymissfit Well-Known Member

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    It's very similar to a .243 AI, but with the 6mm Remington neck and 40 degree shoulders (some of them use 30 and 35 degree shoulders). You cut the chamber with a 6mm AI reamer that is short chambered to the .243 length at the shoulder.
    gary
     
  10. TMR

    TMR Well-Known Member

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    There are a lot of people out there running 115s in the ackley at 3200+. A straight 243 can push them to 3100 to 3150. The ackley has a considerable increase. In case capacity over a 6 dasher. I have several customers running 115s over the 3200 mark. I believe senderoman even posted some data on here using hybrid and hitting that mark easily as well.
     
  11. jacack

    jacack Well-Known Member

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    if i can get 3100 with a 115 in the ackley i would be happy, also what the issue with the neck on the ackley that people talk about

    thanks
     
  12. jacack

    jacack Well-Known Member

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    one more question, if i went with the ackley and chambered it for the 115s will it be short enough to feed out of a magazine? thinking about one of the box magazine kits from badger

    thanks
    jared
     
  13. Long Time Long Ranger

    Long Time Long Ranger Well-Known Member

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    I am getting over 3200 fps with the 107 matchking and 28" barrels in my 243 AI's. 4"-5" groups are regularly shot with the 243 AI at 1000 yards. I can't comment on the wildcat 6mm's off the Remington case because I have never built any of those. The 243 AI is very simple to load for and shoot. I can buy a box of 243 winchester in a pinch and they shoot very well in mine also except for the ones with the tight neck chambers obviously.
     
  14. TMR

    TMR Well-Known Member

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    If your smith has his reamer setup for mag feeding on the 115's it is doable. I designed me reamer to allow me to use the 115's and AI detachable magazines. My OAL is 2.86-2.87. Fits in the mag easily. 3100 is not difficult with the Ackley and 115's.