Barrel Heat

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by royinidaho, May 14, 2006.

  1. royinidaho

    royinidaho Writers Guild

    Jan 20, 2004
    Barrel is Lilja #4 Contour CM beaded w/matt bluing.

    On a 70 degree plus day like yesterday the barrel heats, I would say really fast. 3 well spaced shots and its hotter than I would like. Can hold on to it but its HOT. 5 well spaced shots and you can't hold onto it.

    It also doesn't cool as rapidly as I am used to. When it had the Douglas barrel on it (30 years) I never noticed this kind of heating.

    Usually shot in complete sun light, not many trees in Idaho. Shade does help though.

    Any difference between CM and SS? What about Flutes?
  2. Bart B

    Bart B Well-Known Member

    Dec 25, 2005
    If the cartridge is the same as you used before, one reason the new barrel heats up faster may be due a smaller bore/groove diameter. Or if the new barrel has a much faster twist. If it's rougher than the old one, that can cause a barrel to heat up faster, but usually only during the first few shots.

    Some tests were run years ago comparing four different barrels of the same material, had the same countour ('cept for the fluted one), bore and groove diameters and were chambered for the same cartridge. The differences were one was shiny smooth, another fluted but a bit larger in diameter to have the same weight as the others, one was fine bead blasted and the last was coarse bead blasted.

    Each one heated up a bit faster or slower than another and cooled off the same way. Evidence showed the following:

    Shiny smooth barrel heated the fastest and cooled the slowest.

    Fine bead blasted one was second in heating and third in cooling.

    Fluted barrel was third in heating and in second place cooling.

    Coarse bead blasted heated the slowest and cooled the fastest.

    If you want your new barrel to cool faster, I'd get it coarse bead (or sand) blasted. Fluting it will make it less stiff plus changing the bore and groove diameters; more at the ends of the flutes than between them. If it's a button-rifled barrel, the area between the flute ends will be a bit smaller in diameter with an oversize ring at each end. If it's a hammer forged barrel the dimensions between and at the flute ends will reverse. Hammer forged and button rifled finished barrels typically aren't as accurate after fluting. Bore and groove dimensions won't change much at all if it's a cut-rifled barrel and accuracy usually doesn't change if light fluting cuts are made.

    I don't know if chrome moly heats and cools the same as stainless steel or not. Do an internet search for steel properties, type 4140 chrome moly and 416R stainless; that may give some numbers to help out.

  3. goodgrouper

    goodgrouper Well-Known Member

    Sep 3, 2004
    [ QUOTE ]
    Or if the new barrel has a much faster twist.

    [/ QUOTE ]

    That has been tested over and over and the difference was so minute that it couldn't even be measured during several of the tests.

    The more likely answer is a rougher bore or smaller bore or different metallurgy.
  4. royinidaho

    royinidaho Writers Guild

    Jan 20, 2004
    Barrel may be "small" bored per discussion w/Kirby regarding Lilja barrels.

    Interior of barrel is smooth as a new born baby's butt.... Zero/ziltch/naada copper fouling that is, 40 shots wipe out over night no blue color. Only grungy RL-22 residue

    Shooting 58.9 gr RL-22 and Hor 140 BTSP interlocks @ 3200.

    Outside of bbl is fine beaded w/some kind of a very light (read thin) black finish. Was done by a Lilja recommended smith in Grand Junction Colorado. Who did an outstanding job by the way. Still like those groups in the 1s when the sun/moon/stars line up. /ubbthreads/images/graemlins/grin.gif

    RE flutes: Won't flute this one but the next on is to be a Lilja #7 with 50 cal flutes. Same cal. but much larger case. I think the flutes are a good choice on that one.

    Edited below:

    OBTW - Its a 12 twist and the other barrel, the Douglas, was a 10 and had my own slow rust blue job which was to be a redo of my original slow rust brown (which was beautiful BTW) but when I touched it w/a stainless brush it turned blue. This process BTW puts the toughest finish on metal that I've had on any of my rifles.

    Thanks for the info guys.