Is my twist to fast for a 6/284

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by stifle, Mar 2, 2008.

  1. stifle

    stifle Active Member

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    Hey Gents,
    I just recieved my 6mm barrel from lilja. It is a 1 in 8 twist/ 3 groove and 30 in long. I was planning on chambering it in a .243 but decided I wanted a heater. I was thinking 6mm 284 but I am a little concerned about the 1 in 8 twist at those velocities. Has anybody done this with this barrel and if so what were your results. I am planning on shooting the berger and sierra 95-105. If this is a problem please stop me before I go order the reamers and regret it. Thanks Stifle
     
  2. James Jones

    James Jones Well-Known Member

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    Its not a problem hat barrl should shoot those bulets ok unless you get crazy with the pressures. I personaly don;t think that the extra speed of the 6-284 outweighs the lost barrel life of that round , loose maybe 200fps and you can about double the barrel life with a 6x47 Lapua and it will do everything the 243 Ai will with less powder. A member here "eddybo" has a couple of these guns one that he competse with has over 2000 rounds and is still competitive in the F-class game !!
     

  3. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    If you go with a 107 gr SMK you will be fine. The 115 gr Bergers will also work great in most cases as long as you keep velocity under 3250 fps or so which is about where you will top out anyway.

    The 105 gr Berger and A-Max will not like this barrel at any velocity much over 3250 fps which is a pretty easy job for the 6-284. Just to much baring surface compression on these thin jacketed bullets. At 3250 fps or less, they tend to shoot extremely well but not above.

    The 107 gr will allow you to run the 6-284 to its limits pressure and velocity wise. I have tested them to 3600 fps in a 30" barrel just like yours and accuracy was great, that is to hot of a load however, I just wanted to see where they would top out at, they didn't.

    I dropped back to 3450 fps in my rifle and they shoot extremely well. THe 115 gr Berger loaded to 3200 fps also shoots very well so that may be a consideration as well.

    Kirby Allen(50)
     
  4. stifle

    stifle Active Member

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    Barrel Burner

    What kind of barrel life are you getting out of your 6/284 if you are pushing moderate velocities for the cartridge. I don't mind having a barrel burner but if it is too rediculous I might look at other options.
    Thanks,
    Ron
     
  5. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    I have just over 700 rounds down my barrel, its getting pretty warn. I have had to chase the lands for a while. I have also had to increase the powder charge a bit to maintain velocity because of the loosening throat but accuracy has stayed suprisingly good but yes the barrel is very tired.

    I was not overly nice to this barrel for alot of its life. I pushed her very hard testing bullet performance and doing ballistic testing. Then while long range rockchuch hunting she got heated up more then once.

    The barrel will soon be replaced with a Lilja 1-9 6 groove which is more bullet friendly to the 105 gr Berger and 105 gr A-Max bullets. The A-max is a much better long range varmint bullet as it expands much better then the SMK.

    Still, you put the 107 where it should be and it works very well. It actually performs better on larger critters such as yotes, pronghorns and deer then smaller varmints.

    Kirby Allen(50)
     
  6. buffalorancher

    buffalorancher Writers Guild

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    Everything Kirby said is right on as far as my experience with my 6-284. My rifle has an ABS carbon wrapped 30 inch 8 twist 5r Rock and shoots the 107 gr. SMK very well. It is picky to load for and the A-Max and Wilcat bullets would smoke easily. I've shot probably 20 whitetail does in the last 2 years and the 107 SMK works well on them out to about 600 yards, after that it's a pencil hole all the way through. We've got terrible mange right now so coyotes are hard to come by but I've nailed 3 out to 300 yards and this bullet made a hell of a mess. If I did it again I would do a 243 and maybe AI it. I can't get 6x284 velocity to go along with accuracy and I've stopped trying because of barrel life.
     
  7. velocity-is-key

    velocity-is-key Member

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    VLD = less bearing surface...have spun the 105 to 3700 in 1:8 with no problems..just remember the ogive is further away than the norm so chase the lands. Mine likes .120 off the lands and thats typical for the VLD 6mm though far off...I'm talkin one ragged hole groups..higher velocity will stabilize a slower than ideal twist rate/bullet combo also. EX: 115s at 3100 FPS poor groups .3s, 115s at 3600 FPS .1s groups...really.....Don't be afraid to go against the flow it may surprise you with the results..BUT WATCH THAT PRESSURE!..cartridge was a mild innocent fully blue printed .0015" under NK dia. 6mm/300WBY.....1.400" krieger bull at 26". something to ponder on when you feel the berger can't handle velocity...
     
  8. Trickymissfit

    Trickymissfit Well-Known Member

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    a 1:8 twist will work just fine, but your also better off shooting bullets with a high B/C number. Not real sure how well the .284 case works with reduced loads, but sure somebody here would know.

    I used to shoot a lot with some guys that were really into the 6/284, and they usually went thru a barrel a year! Then one of them reamed his chamber .100" short at the shoulder, and nearly doubled his barrel life. He lost less than 100fps in a 26" barrel (actually about 75fps). Then another guy did exactly the samething, but chambered it .150" short. It shot even better, and there was no real difference between the two short cases (still less than 100fps). But they were saving four or five hundred dollars a year in barrels. This kinda falls right back to some of P.O. Ackley's writtings; where he said that the 6mm remington case was about it for the .243 round. Myself; I'd build a 6mmAI, and never look back.
    gary
     
  9. FEENIX

    FEENIX Well-Known Member

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    I hope the OP did not wait 3 years for the project, it would have driven me nuts if it was me.