.243 ai vs. 6mm-284

Discussion in 'General Discussion' started by j_22250, Nov 26, 2007.

  1. j_22250

    j_22250 Well-Known Member

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    Hey Guys, new here to the forums. I hate to post a new tread on an old topic; especially on my first post.

    I pretty much had my mind set on a .243 ai, but after seeing a post about the ultimate 1000 range varmint rig I started to reconsider and had a few questions. I'm planning to build on rem adl short action. I know the 6-284 will fit, but am not sure if i will be able to play with the seating depth and different bullets all that much (100gr factory 6mm ammo clears mag. but is close) especially with ballistic tips I know they are usually a little longer than plain old soft points.

    Quote:

    "The 6x284 is number 1 because of the combined qualities; Velocity, Accuracy, Retained energy down range, Low recoil and brass selection."

    I know that greater impact velocity = greater energy, but how much more powder does the 6-284 use to gain how much more velocity over the .243 ai. Better retained energy usually comes with heavier bullets, and brass selection is not to great either. i already have 243 brass and making brass is alot eaiser and cheaper for the 243 ai. Small gains probably wouldnt be that impessive to me, but it sounded like the 6-284 might have some real advantages over the 243 ai. i also feel like the .243 ai would burn powder more efficiently due to a shorter stubby case.

    I'm not tring to start a pissing contest here, but I would like to here some 1 elses opinion berfor I make a final decision.

    I guess i should add more info on what im planning for my build. a 24" barrel with a 1-10 twist and plan on using hornady 87gr. v-max or 87gr. bthp. longest shot ever taken was around 450yrds so not so much of a 1000 yrd. gun. More like 500-750; 800 yrds tops or else i would get faster twist and hevier bullets.(knowing my gun could pull off a shot like that would be awsome). I dont want to go smaller on the bullet weight either cause i might have to shoot the ocasional deer with this rifle. Also curious if any one has shot a yote with a barnes tsx.

    I apoligize for the long post, I just sort of kept going.
     
  2. j_22250

    j_22250 Well-Known Member

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    Gosh, i joined the forum cause i couldnt find a search feature and overlooked it after i became a member. I have found alot of the answers that i was looking for now, but am still curious about just how close together these cartridges are. Since i'm going through the trouble and expence to build my ultimate yote/deer rifle i couldn't bear the thought of knowing that i could have gone with something slightly better. I'm hoping to achieve a muzzle velocity of 3400fps with an 87gr. bullet and be able to shoot 1/2" - 1-1/2" groups out to 300 yards. To me this seems pretty realistic any faster and i would be concerned about the bullet coming apart faster than it should on deer sized game. Load data on either of the two would be appreciated
     

  3. LewisH

    LewisH Well-Known Member

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  4. j_22250

    j_22250 Well-Known Member

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    thanks for your reply lewis, i have visited several sites including this one (varmint al, reloaders nest, graymist44, 6mmbr.com and others) most load data that I have found seems to be focused more around the hevier type bullets for competition and the lighter stuff for varmints though. Also I have found that the case capacity for the .243ai and 6x284 are about the same. With the exeption of a hot load for the .243ai would be about a medium one for the 6x284 with only about a grain of difference. Seems like to me that the 6x284 might only be faster by around 100fps and if i am able to achieve 3400fps with the 243ai it may be a better choice cause of its shorter length. guys with experience on these two cartridges please correct me if I am wrong.
     
  5. uncleB

    uncleB Well-Known Member

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    Are you serious or trying to be a comedian ??? ("I have found that the case capacity for the .243ai and the 6x284 are about the same").
    Let me know what direction you are headed and I can help you out either way.
    UB
     
  6. j_22250

    j_22250 Well-Known Member

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    sorry i havent replied sooner i just returned from a phesant hunt. NO I AM NOT TRYING TO BE A COMEDIAN. OBVIOUSLY YOU DIDN'T READ THE FIRST TWO POSTS. Anyways in my hornady reloading manual with an 87gr. bullet the max load for the 6x284 of 47 grains of RL-19. velocity of 3100fps. Max load for a .243 win is 45 grains of RL-19 at 3100fps. So I'm just guessing the ai version will hold 2-3 grains more.

    P.S. don't reply like an idiot. If I already knew I wouldn't be asking, since replys have come up short this is just something that i looked up pretty quick in the hornady manual. I am looking for a reply from sombody with first hand experience.
     
  7. CatShooter

    CatShooter Well-Known Member

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    Not hardly.

    The 6mmx284 is about 10% larger than the 243 AI.

    That's nothing to sneeze at - the 6mmx284 is in a whole 'nuther class of cartridges.

    You might wanna do some more research before you loose your head over this one (literally)... you obviously been given bad info.

    .
     
  8. Coyboy

    Coyboy Well-Known Member

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    I built a 243AI with a 28" Lilja 3 groove 10 twist. My fireforming loads with 85 grain bullets run at 3400fps. Loads with formed cases run comfortably at 3600fps with 85 grain bullets. I had them as high as 3700 in testing, but they showed some excessive pressure signs. 3600 is a comfortable load and accuracy is sub .5 moa. Thin skinned bullets have let lose when pushed hard in this gun.
     
  9. j_22250

    j_22250 Well-Known Member

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    Thanks for the info guys.

    :confused: Gosh, I hope I don't lose my head over this, I might lose my mind though.:eek: HUH... I guess I need to call Hornady and complain about the bad info.:D

    By how much more of a class is the 6x284 in when compared to the .243 ai? This kinda brings me back to my original post. How much more powder will fit in the 6x284 and how fast will it push a 85-87gr. bullet? Then when compared to the .243 ai how close are the achieved velocities and with how much less powder can the .243 ai achieve around the same? Im kinda trying to compare the same powder for both.
     
    Last edited: Dec 4, 2007
  10. uncleB

    uncleB Well-Known Member

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    j_22250,
    I cant believe you got so butt hurt by my comments, but from your post I did not know what direction you were going.
    After reading catshooters post I thought his estimate of a 10% capacity increase was a bit modest, so to answer your question I took both a 243ai case and a 6-284 case and filled them both to the bottom of the neck with Win748 (a ball powder that flows almost like water) the 243ai case held 53.5grains and the 6-284 case held 66.2grains. even accounting for variables such as different reamer specs. etc. the difference is closer to 20%.

    As far as velocity difference with 85-87gr bullets I truly dont know because I only use this class of cases with 95-107gr bullets. with 95-107gr bullets you can expect at least a 200fps increase. just something to think about if you want to shoot 85-87gr bullets you might want to consider a 6BR or a 6BRai you give up a little velocity but gain substantial barrel life.
    UB
     
  11. CatShooter

    CatShooter Well-Known Member

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    Unka B... but you know that I'm modest ;) ;)

    The 6mmx284 is nothing more than a 6mm-06, and there's no way in hell that a 243 in ANY version can equal a 6mmx284 or a 6mm-06.

    .

    Good post!!


    .
     
    Last edited: Dec 5, 2007
  12. alf

    alf Well-Known Member

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    6-284!!!

    Can't you hear the 6-284 singing to the 243AI:
    "What ever you can do, I can do better"?
    To compare the lighter/midweight bullets, these two are pretty close.
    But the bigger case always shines brighter with bigger bullets.


    Al.
     
  13. j_22250

    j_22250 Well-Known Member

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    So in other words what it takes the 6x284 10%-20% more powder, the 243 ai can come very close with less(with middleweight buletts of course). It's a safe to say that if you want to shoot 85-87 grain bullets a .243ai would be a better choice; pushing these lighter bullets any faster than velocities attainable by the 243 ai and bullet construction would definiatly have to be considered.

    Another thing I did however find interesting was a guy who was gonna build a 243ai and opted for a 6mm22-250 instead. He could achieve close to the same velocities with around 12% less powder.


    I don't like BR's for some reason.
     
    Last edited: Dec 5, 2007
  14. CatShooter

    CatShooter Well-Known Member

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    Lemme see...

    "So in other words what it takes the 6x284 10%-20% more powder, the 243 ai can come very close with less(with middleweight buletts of course)."

    And...

    "Another thing I did however find interesting was a guy who was gonna build a 243ai and opted for a 6mm22-250 instead. He could achieve close to the same velocities with around 12% less powder."

    So, since a~=b~=c.

    We have the 6x284 almost equal to the 243 AI which is almost equal to the 6x22-250 (6mm International).

    So a 6mm case with 60 gr of powder is = to a case with 42 grains of powder, is equal to a case with 35 grains of powder??

    So we have the 6x22-250 almost (kinda) equal to the 6x284??

    I'm gonna build a .223 Rem that is almost equal to a 22-250, which is almost equal to a 22x243,which is almost equal to a 22x284... or is the other way around??

    I L-O-V-E this website.


    .