barrel cool-down

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by skandlus, Sep 18, 2009.

  1. skandlus

    skandlus Well-Known Member

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    to get the best groups, how long is an adequate amount of time to wait between shots to let the barrel cool down? im shooting a rem700 6mm....
     
  2. Michael Eichele

    Michael Eichele Well-Known Member

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    IMHO, a barrel worth its salt is going to shoot good groups firing shots back to back to back.

    I tend to give my 338 EDGE 3 minutes between shots for barrel life purposes yet I shoot my 308 one right after another up to 5 shots. It has been known to shoot 5 shot groups in the area of .3" at 100 yards.
     

  3. Gene

    Gene Well-Known Member

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    Because of expansion and contraction, there is no way to quantify this. At the range with competition rifles, I shoot until the barrel is just starting to get hot to the touch. Hunting rifles are different. You want that first shot from a cold barrel to count. So, for those rifles, I think its best to completely cool the barrel between shots.

    Also, on some over bore capacity rifles, like the .257 Weatherby, for example, overheating can accelerate erosion of the chamber pretty quickly.
     
  4. Mikecr

    Mikecr Well-Known Member

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    If you want best cold barrel shot consistancy(which is what this site should be about), then give it as long as it takes..
    If hot group shooting is your thing, I'd ask em at BenchrestCentral.
     
  5. Nomad

    Nomad Banned

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    What one of our training officers has us take the weapon off line
    when it becomes hot to the inside of our wrist at a touch , then place the weapon
    in the rack with bolt open to draw cool air through the action to bring down
    barrel heat quicker.
    At another school they had a heat indicator and said not to go over 160 degrees.
     
  6. Gnarly

    Gnarly Active Member

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    The jury's still out,for me!

    I'm using the self-adhesive Temp Strips from McMaster-Carr, to try & measure barrel temps.They are on the tops of the barrels,just under the front of the scopes.

    But haven't had enough time off to really test them.

    ----Gnarly
     
  7. J E Custom

    J E Custom Well-Known Member

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    With this caliber you should be able to get 2 or 3 shots off before the barrel needs time
    to cool. check it with the back of your hand if it feels uncomfortable stop and let it cool
    down 5 to 10 min.

    If you have a sporter weight barrel this will be about right ,With a heavy barrel 4 or 5
    should be no problem.

    And as stated if you shoot the big cartriges ( 100+ grains of powder) they will heat up
    much faster. I had a 30/378 with a #3 contour barrel and after only one shot of 122grs
    of powder you could feel the heat and after 2 or 3 shots I needed to wait

    Some match rifles must shoot 10 to 20 rounds in quick order but they are normally heavy
    barrels and even though they get hot the heavy barrel absorbs and distributes the heat
    better.

    I have one of the infrared temp readers for checking exhaust temps on race cars and it works
    well for barrel temps and is easy to check any location on the barrel.

    But if you use the back of your hand you will never over heat a barrel.

    J E CUSTOM
     
  8. Mikecr

    Mikecr Well-Known Member

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    Heavy contour barrels don't improve barrel life. It isn't barrel life that's led to use of these in competition. It's benefit is lower POI change over a high temperature shift(stability).
    Of course a heavier barrel takes longer to heat up with a given input of energy. That heat is bottled up in more mass, and eventually breaks at a larger surface/diameter. That same heat is felt quicker at the surface of lighter contour barrels. That's all.

    Means nothing w/regard to throat temps, and that's where barrels meet their demise. Higher energy catridges(than 6PPC, 223, 30br, 308, etc) for bore, will heat a throat to a point of detriment very quickly, regardless of barrel contour, or overall temp. You have to give that energy a chance to move away from the throat.
    So if barrel life is really your concern, for group shooting, the back of a hand check is very flawed.
    Group shooting guns are low energy.
    Hunting guns are not group shooting guns.

    A friend eventully learned some of this with his favorite deer gun, a 25-06 which was very accurate. He used the gun for many years but all the sudden he got caught up chasing ever tighter groups, and bringing them into work for show & tell. 3-shot groups, fast as he could, then 30min cool down between each group. He never let the barrel 'feel' hot.
    I thought,, -what a shame he's killing that barrel.

    One day he says somethings wrong, & it seems like he has to seat the bullets out further(than logged) to regain tune. He's wondering why that is with just under a thousand round count. 'Never seen anything change before'.
    I told him that 3rd shot in each group was ripping throat away. It's too much energy right there, so give it about a minute between shots.
    Didn't make sense to him, he couldn't group as well, everybodys group shooting..
    Within the next couple hundred, he finds that he cannot stay in tune through a full sitting, and is shopping for a gunsmith.
    Ruined a great barrel he and his son could have hunted the rest of their lives with.
    Now he's caught the bug and is full blown 30br score shooting.
    Doesn't hunt anymore..
    Guess that was what he really wanted.

    Think about what YOU really want.