will heat (barrell)open up groups at 700 yards?

Discussion in 'The Basics, Starting Out' started by 30-06 boy, Dec 12, 2005.

  1. 30-06 boy

    30-06 boy Well-Known Member

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    i have a sporter wieght barrell(30-06) and am concerened if groups will open up as the barrell heats up during shooing at 700 yards? planning on 5 shot groups shot at 1 minuite intervals.will be doing most of my shooting around 30 degrees.jason
     
  2. Ballistic64

    Ballistic64 Well-Known Member

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    I would venture to say that any variable will open up groups at 700 yds.
     

  3. arthurj

    arthurj Well-Known Member

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    Excessive barrel heat will open your groups up at any yardage. With a sporter weight barrel you will probably limited to three or four shot groups with a 1 minute interval. I would personally keep it at three.
     
  4. 4ked Horn

    4ked Horn Writers Guild

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    Just a thought. Look into your bullets velocity at this distance for the conditions and see if you are going subsonic around this distance. The bullet may be losing stability an your groups will fall apart.
     
  5. HoytemanPA

    HoytemanPA Well-Known Member

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    I shoot three, not rushed but as fast as comfortable. If you wait a full minute between shots, you will end up with a plot graph of the wind conditions of your range moreso than the accuracy potential of your rifle. Many groups of threes. With an '06 skinny heat from 5 doesn't noticeably affect groups but with a mag skinny I have had groups start to open at around 4 or 5. With a heavy barrel I still shoot groups of threes but a lot more of them.
     
  6. Guest

    Guest Guest

    I can tell you now that UNLESS he's shooting "squibb" loads....the bullet isn't ANYWHERE NEAR SUBSONIC at 700 yards!

    MERRY CHRISTMAS TO ALL!!
     
  7. 30-06 boy

    30-06 boy Well-Known Member

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    maybe i have confused some of you.i was just wondering if 5 or 6 shots shooting them at 1 minuite intervals would open up groups excessivley .i'm not going to shoot the rifle untill i can't touch the barrell.i know that would not be good.but under conservitave 4-5-6 shots.i am starting to load for a 30-06 and would like to know about when to stop shooting because the gun is starting to heat up and affect accuracy.
     
  8. arthurj

    arthurj Well-Known Member

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    The only way to figure it out is to try and see when groups open up. Some barrels might hold up for 3 shots and another will hold for 5. It would of course depend on the air temp that day. I had a 7 ultra mag that got hot fast, and tried to give it those intervals between shots. I found that a minute really isn't as long as it seems when youre trying to cool steel.
     
  9. Bart B

    Bart B Well-Known Member

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    It depends on two things; what kind of barrel it is and how it's fit to the receiver.

    Most factory production barrels are not well stress relieved. Which means as they heat up they will bend. The group may shift center but usually doesn't get larger.

    Most custom match-grade barrels are very well stress relieved and they don't bend as they get hot. Best example of this is when a friend took his Win. 70 based .308 Win. target rifle with a stainless Hart barrel, clamped it in a machine rest (unrestricted, free recoil) then fired 40 consecutive shots about 20 seconds apart starting with a cold barrel. That barrel was pretty darn hot when he finished. So was the 40-shot group 600 yards down range; 1.9 inches.

    If your receiver's not trued square with the barrel tenon thread axis, the barrel will fit hard at one point around the receiver ring. This can cause a slight stress that can cause barrel bending in that direction.

    And a round left in a hot chamber over 15 seconds can heat up to have a higher muzzle velocity which means it'll strike high.
     
  10. Guest

    Guest Guest

    Bart

    << Best example of this is when a friend took his Win. 70 based .308 Win. target rifle with a stainless Hart barrel, clamped it in a machine rest (unrestricted, free recoil) then fired 40 consecutive shots about 20 seconds apart starting with a cold barrel. That barrel was pretty darn hot when he finished. So was the 40-shot group 600 yards down range; 1.9 inches.>>

    Hmmmm.....that wouldn't have been Mid T. would it??

    Best thing that EVER happened to him....is NANCY!! /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif