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6mmRem to a 243Win.

Discussion in 'Rifle Country' started by Samclrk, Aug 25, 2013.

  1. Samclrk

    Samclrk Well-Known Member

    OK...If I buy a 6mm Rem.rifle and then rebarrel it to a 243..Can I shoot loads from the 6mm charts..And exactly why not..?
  2. squarepants33889

    squarepants33889 Well-Known Member

    I'm not sure if I am over or under thinking this. Maybe I will sit back and see if it clears up.
  3. morcey2

    morcey2 Well-Known Member

    No, you can't. Why not? Same reason you can't shoot 22-250 loads in a 223 case. They share a caliber, but that's it. The question actually doesn't make much sense.

    If you want to keep the 6mm velocity, keep the 6mm. It sounds like you're planning on hand loading anyway, so it shouldn't be an issue. I'm building a 6mm Rem on an 1909 Argy receiver. I like the longer neck on the 6mm as compared to the 243, but they're both good.

  4. Jim Watson

    Jim Watson Well-Known Member

    The 6mm is better anyhow, unless you depend on buying ammo at Cheapmart.
  5. toiville2feathers

    toiville2feathers Well-Known Member

    I personally wouldn't rebarrel or rechamber a 6M/M Rem to a 243. For the most part I would consider that a step backward. The only advantage I think would be the availability of brass.
    The 6M/M is similar to the 244 Rem. The 244 rem has a slower twist rate than the 6M/M and the 243 and could only stabilize light bullets.
    The 243 was introduced to compete with the 244 and gained popularity because the 243 would shoot heavier bullets for hunting big game. Remington then come out with the 6M/M, but was to late to gain much popularity, even though it was a superior cartridge.
  6. Abel

    Abel Well-Known Member

    Why would you rebarrel to 243???

    And why would you not want to use the 243 loads...since the brass/case is different?

    And again, if you already have a 6mm, why rebarrel to 243?

    This reminds me of the book Catch 22. The only reason to rebarrel the 6mm is to go up to 7x57 or 257 Roberts....or to rebarrel to another 6mm with a bit faster twist to handle 100 grain bullets better.
  7. morcey2

    morcey2 Well-Known Member

    If you did happen to buy a 6mm with a slow twist (as toiville2feathers is referring to) I would rebarrel it, but it would stay 6mm, but with a 1:9 or 1:10 twist.

  8. Samclrk

    Samclrk Well-Known Member

    Thanks for the replies.
  9. ETXhiker

    ETXhiker Well-Known Member

    Do you mean can you use 6mm loading data after you rebarrel to .243? The answer to that would be no. Smaller case=higher pressures.

    Seriously, 6mm is the superior cartridge. If you buy it, leave it alone. Still plenty of ammo for it.
  10. Samclrk

    Samclrk Well-Known Member

    ET,yes.That was my question..Thank you
  11. gunownerz

    gunownerz Active Member

    Most wouldn't advise you to do so in the first place. Leave the 6mm barrel.

    Short answer is no. It isn't advisable to shoot ammunition down the barrel that is meant for a different caliber...... ever.
  12. W.E.G.

    W.E.G. Well-Known Member

    You can buy an already-a-243 for the less money you can buy a 6mm and re-barrel to some other caliber.
  13. planetmobius

    planetmobius Well-Known Member

    The 6mm is a superior round. Keep it.
  14. Outlaw Man

    Outlaw Man Well-Known Member

    I know a guy who did exactly this. The gun was scary accurate before, when I shot it. He's noting improved accuracy and performance.

    Seriously, if you're hand loading, go with the 6mm. The .243 is a decent substitute if you're only buying off the shelf ammo.
  15. sixgunner455

    sixgunner455 Well-Known Member

    There's nothing wrong with the .243! But, there's nothing wrong with the 6mm, either. The .243 has the market share. If I'd gotten a 6mm instead of my .243, I wouldn't be thinking about re-barreling it. I'd be looking for brass! :D
  16. Samclrk

    Samclrk Well-Known Member

    I realize the 6mm is more powerful.but is it as accurate?Or more so?..I only shoot at paper.
  17. Woolecox

    Woolecox Well-Known Member


    6mm and 243 are the same bore diameter. Why would you replace the barrel with one of the same size? The chambers are different. The 6mm Rem has a higher case capacity, exactly 1 grain in terms of powder charge.

    The 6mm Rem will push a 107 grain pill about 50 fps faster than a 243 Win. Both are excellent cartridges and can be made to shoot as accurately as you want to spend. Obviously the 243 Win being the most popular and having the greatest availability of components.

    I built a 243 Ackley Improved. It pushes the 107 bullet at 3200 fps with a conservative load and 3300 fps with a hot load (26" barrel). But you can also wildcat the 6mm Rem to and AI version an outdo the 243AI slightly. The ballistics on this bullet are outstanding.

    You can expect to re-barrel all the fast 6mm's after about 1000 rounds. Performance has its price.

    I do love my 243AI. I'm on the second barrel.


    Fire formed 243AI case

    Last edited: Aug 28, 2013
  18. 303tom

    303tom member

    NO, because it will not fit !....................Yes You Can !...................
    Last edited: Aug 28, 2013
  19. Samclrk

    Samclrk Well-Known Member

    Thanks..I might consider the 243AI.,,I`m wanting the 243 ,but I`m asking if it`s safe to shoot the 6mm Rem. loading charts of the 6mm Rem.in a 243 chamber.Everybody is saying no..Thanks,everybody for commenting.
    Last edited: Aug 29, 2013
  20. Samclrk

    Samclrk Well-Known Member

    Thanks,Mr.Woolecox..Nice looking rifle.

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