Bench Mark 3 grove button rifled

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Iron Worker, Mar 11, 2009.

  1. Iron Worker

    Iron Worker Well-Known Member

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    First are 3 grove BBLs tough on bullets? I need a new Barrel for my 6x284 currently I have a Hart and its about shot out? I was thinking of a Cut rifled BBL but speaking to this staff person at Bench Mark barrels has me thinking?
     
  2. James Jones

    James Jones Well-Known Member

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    From my experiance the 3 groove barrels are harder on bullets , the lands are bigger and work the jacket more.

    If I were planning to build a real hot rod I'd use a cut rifled barrel from either Rock Creek or Bartlein with the 5R rifling , Broughton also makes a 5R barrel but its buttoned rather than cut.

    I'm not sure that their is any real differance in barrel life with the buttoned compaired to the cut barrels but I have seen a marked increase in velocity with the 5R barrels over conventional land and grooves.

    You can't go wrong with a Kreiger or Brux 4 groove though
     

  3. J E Custom

    J E Custom Well-Known Member

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    There has been a lot of discussion on this question so do a search on 3 grove barrels
    and it will answer your questions.

    I have limited experance with 3 grove barrels but the ones I have dealt with are very
    good.

    Mine have all been slow twist for ultra high velocity (1 in 15).

    J E CUSTOM
     
  4. James Jones

    James Jones Well-Known Member

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    Yep , their should be alot of info in the search files , I remember Kirby Allen doing some test and such with his Allen mags , If I rememer correctly he had Lilja make some barrel that used thinned lands or somthing for his hot 257 or 270 for use with the realy long Wildcat bullets
     
  5. J E Custom

    J E Custom Well-Known Member

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    James.

    Kirby did have problems with the 3 grove barrels but as I understood him to say they
    were all fast twist for heaver bullets and the thin jacketed bullets came apart at high velocity.

    Based on every ones experiance and recommendations I went with the slower twist for lighter
    bullets hopeing I would not have the same problems.

    So far I am pleased with the test I have done( break in loads were with 60gr .223 dia bullets)
    and they produced a velocity of 3915 ft/sec and a SD of 6.

    The next bullets I will try will be 50gr @ around 4200 ft/sec. and then 40gr bullets @ around
    4400 ft/sec.

    So before I could recomend 3 grove barrels I have to do more test.

    I am still hopeing my experment is a success.

    Thanks
    J E CUSTOM
     
  6. jwp475

    jwp475 Well-Known Member

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    IronWorker is talking about an 8 twist, I'd cal that a fast twist. He also is talking about a 6-284 with High BC bullets driven fast.
     
  7. J E Custom

    J E Custom Well-Known Member

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    Yes I hear you .

    Not sure how fast the 6-284 will push the bullet he wants to use.

    Maybe Kirby will chime in and render his opinion on this combination.

    We all seem to gravitate towards fast twist barrels because of the bullets we
    use for longrange hunting/shooting so this was a leap of faith for me going to
    a 1 in 15 twist.

    J E CUSTOM
     
    Last edited: Mar 13, 2009
  8. buffalorancher

    buffalorancher Writers Guild

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    I have a Rock 5R in a 1-8 twist on my 6-284. After about 300 rounds the A-Maxes and Begrer's started to smoke. If I remember right, Kirby reccomended a 1-9 twist as a balance of speed and twist to keep bullets together.
     
  9. uncleB

    uncleB Well-Known Member

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    Just as a rule of thumb,
    The faster the twist,the greater the powder capacity the worse a 3 groove becomes.
    (222rem. 1-14" twist awesome, 6mm-284 1-8" twist horrible).
    UB
    p.s.
    If I were to be 100yards away I would let you shoot me with my 6mm-284 1-8" twist 3 groove with 105gr A-Max, because I am 100% certain the bullet would not come with in 75 yards of touching me.
     
    Last edited: Mar 14, 2009
  10. royinidaho

    royinidaho Writers Guild

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    Hmmmmm,

    My 270AM is one of the early ones. 3 groove Lilja with a 7 something twist, I think.

    169.5 WCs, which are/were a taped jacket, heavy on the back end were a dream up to as fast as I could get them going. Well over 3300 just for kicks.

    However, the 195 with its much longer bearing surface was on the ragged edge of destruction at 3050. After a few of these were shot about 3 of 5 never made it to the 200 yd berm. Emperical data indicates that 50% of the Lilja 3 groove fast twist bbls began dusting the 195s after somewhere around 400 rounds. The other 50% have not problems, yet. Go figger.....

    Berger 150 held together but couldn't take the punishment of being launched into that twist at only low velocities for the AM.

    If I recall correctly there may have been/be similar problems with the 7 AM and 200 grain WCs. Again, if I recall correctly a fella tried several different barrels and ended up with a Broughton 5R before things became perfect.

    I've been considering a Schneider barrel for my next build to get away from the rifling problems. However, it will most probably be a 10 twist 375 bore.
     
  11. Iron Worker

    Iron Worker Well-Known Member

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    That is some really helpful information. I've got no money to waste. Any how I sent a PM to Kirby and have not received a reply . Maybe he's hunting or is backed up business wise. I want him to install the 6 groove 9"twist Lilja bbl. If he can't take the work any other gun smith do you all recommend?
     
  12. royinidaho

    royinidaho Writers Guild

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    Kirby will most probably take the work.

    Any other smith on here would be ok.

    308 Nate does well. Just ask James Jones.

    When I asked Dan Lilja, before the days of this forum, he recommended Ray Montgomery of Grand Junction Colorado. He did a super job on the #4 barrel and Mauser action. 270 Win. Replaced the shot out douglas barrel of over 30 years. Smallest group = 0.011, on the fridge. Most are around the 1/4 mark.