Rifle barrels that will withstand a barrel burner caliber - 6.5X68S

Discussion in 'Gunsmithing' started by Gert Odendaal, Apr 11, 2019.

  1. Inline6

    Inline6 AH Veteran

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    Gert,

    Maybe tell us how many rounds you would like to get out of your barrel. We can help make suggestions on rounds that meet that requirement.
     

  2. Graham Hunter

    Graham Hunter AH Fanatic

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    Bruce at what point are you calling a barrel burnt out. What size of group at 100 yds do you consider no good.
     

  3. Gert Odendaal

    Gert Odendaal AH Elite

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    Bruce/Inline much appreciated ...Am I correct if I use a heavy for caliber bullet in the 6.5x68S to get a longer life from the barrel..I will not shoot light bullets ..I like to use the most weighted bullet possible for the 6.5x68S caliber...this will be to my advantage when shooting in the wind???all shooting /hunting will be as a hunter ..at the shooting club as well..We shoot twice a month..each table we shoot is about five rounds at 300 meters( three minutes) , then walk to the 150 meter ( five bullets three minutes ) walk to the 50 meters shoot (three minutes )
    I only shoot one tabel...Hunting is twice a year ..I do not think I will use it to hunt since I do bush veld hunting..walk/stalk on foot...with my other calibers..
     

  4. Inline6

    Inline6 AH Veteran

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    What size targets are we talking about?

    I like the 130s in a 6.5, they have a good bc and you take less recoil. Depending upon target size at 300 yards wind would really have to be getting it to push you off target.
     

  5. bruce moulds

    bruce moulds AH Elite

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    graham,
    those barrels were in an fclass rifle.
    for that competition you really need better than 1/2 moa.
    however very few rifles will do that for 20 shots, contrary to urban myth.
    we see so many reports of 1/2 moa rifles that I wonder why people use custom gunsmiths , custom barrels, custom actions, and sophisticated reloading techniques.
    it so often turns out that some guy jagged a lucky 3 shot group, and assumes his rifle is a 1/2 moa performer.
    in my case I can still shoot fclass at club level when a barrel goes out to 1 moa, and you can see this from plot sheets.
    at longer ranges it is vertical in the group you have to go by, as wind deflection has more scope for human error.
    by this stage you have chased the throat with seating depth, and adjusted powder charges accordingly, until such things do not help any more.
    looking at those throats with a bore scope answers all the questions.
    sometimes if you get it early enough, a rechamber will give a bit more life to a barrel, but on a hunting rifle barrel this is often not possible due to barrel external dimensions.
    you might say these barrels will still be useful for hunting accuracy wise, and you would be right, but not for many more shots.
    I have also had this in rifles used for serious culling.
    accuracy will drop off some, and can the just go away completely.
    you do not want to be in the field when that happens.
    bruce.
     

  6. Graham Hunter

    Graham Hunter AH Fanatic

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    Thanks Bruce. I was just trying to see what scenario we were looking at. I have burnt out several bbls. But at a much higher round count than you were indicating. But the requirements of group size were more than F class. On this forum I am just trying to be practical on 300 to maybe 400yds if the shooter has the ability to shoot accurately at those distances. Thanks again for answering my question.
     
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  7. bruce moulds

    bruce moulds AH Elite

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    graham,
    those barrels went faster than a hunting barrel, due to rate of fire and lengths of strings.
    I would still like moa barrels/rifles for hunting the ranges you mention.
    I moa is 4" at 400, so adding shooter error and trajectory into a point blank scenario the shooter would still need to be a very good shot and there be very little wind.
    bruce.
     
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  8. Graham Hunter

    Graham Hunter AH Fanatic

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    Absolutely agree Bruce!
     

  9. bruce moulds

    bruce moulds AH Elite

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    I find a lot of the claptrap about 1 shot kills at 1 mile+ by military snipers a bit interesting.
    a 1 moa rifle (possibly optimistic) would shoot 17.6" at 1 mile if it holds that accuracy to that distance.
    add on some shooter error.
    add on target movement both up and down and left and right due to mirage.
    add on muzzle velocity variation (be aware that 10fps difference is noticeable at 1000 yds, and military ammo would not come close to 10 fps)
    add on wind deflection .( there is no way of measuring wind speed all the way to the target, and at the various heights of trajectory)
    add on the wind conditions can and do change during time of flight.
    any hit is a lucky one:Wideyed:
    strangely many hunters believe the stories and assume such things can also be done on game.
    this suggests nil experience with long range shooting.
    many of the same shooters take no account of what is required in terminal ballistics for the job in hand.
    if they had an inkling of the inhumane results of such so called hunting they might not do it.:A Bang Head:
    bruce.
     

  10. Graham Hunter

    Graham Hunter AH Fanatic

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    Personally I won't watch the long range (hunting) shows. I know one cameraman who quit after getting tired of seeing animals shot multiple times or wounded and lost. The other thing to the long range sniper is the time it takes for a bullet to travel a mile or more. I forget the exact number of seconds but it was more than enough time to bend over to tie your shoelace or step out of the way.
     
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  11. Inline6

    Inline6 AH Veteran

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    Bruce,

    I enjoy reading what you write, it obviously you know what you are doing.

    I'm not a Sniper I don't have that skill set. I do squeeze a trigger every now and then. I have center punched targets (1/2 moa) at a mile cold bore. I have also missed 4'X4' targets at 1500 yards after shooting most of the day (due to wind and mirage). I have shot 3/8" ( not MOA) at 300 yards (5 shots) and have miss 10" plates at 500 yards. The miss at 500 yards was due to adjusting the magnification ring on the scope move it from 15X to 25X caused an impact shift. I have shot over targets due to light conditions. The more you shoot the more you see. I test gear out if it does not perform I send it down the road. I like stretching it out, the better you hit at distance the better you hit up close.

    I have people ask me how far can you shoot a deer, my response is always the same. What are the conditions...it's about knowing what you and your system are capable of.
     
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  12. bruce moulds

    bruce moulds AH Elite

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    good post inline6.
    it is obvious you have done enough to realize that at long range, sometimes you get the chicken and sometimes you get the feathers.
    it is up to us to guarantee the chicken each and every time, and that means being honest with yourself.
    bruce.
     
    Last edited: Apr 30, 2019
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  13. Gert Odendaal

    Gert Odendaal AH Elite

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    Thank you Bruce, maybe you are the person whom I need to explain in a clear, simple manner the following term so I can understand MOA long distance term:
    I moa is 4" at 400
     

  14. Gert Odendaal

    Gert Odendaal AH Elite

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    Inline, great post and a lot of good sense information...your advice would serve a lot of hunters on good stead...I have found for myself (I am not shooting long distance ) if I start practicing shooting my compound bow for a month before a hunt..I really have a much better sight picture at a rifle target and better grouping...I used to practice at 80 meters with my compound bow back to fifteen meters....my breathing stabilize and ensure better accuracy...(y)(y)
     

  15. Gert Odendaal

    Gert Odendaal AH Elite

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    Not to stray from this great informative discussion. ...long range shooting scenarios, barrel life, methods to improve barrel life , target barrel life versus hunting barrel life, heat erosion in rifle chamber leading to increased/faster shooting out of barrels has been covered...can we focus for a while on bullets /bullet selection for these barrel burners, bringing in account the importance of SD as well as BC when shooting these bullets in the 6.5 x 68S barrel burner caliber...
    Here is a link to a type of hunting bullet..do you members care to reply on this video?
    https://www.hornady.com/ammunition/rifle/6-5-creedmoor-143-gr-eld-x-precision-hunter#!/
     

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  16. bruce moulds

    bruce moulds AH Elite

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    gert,
    1 minute of angle is the angle the earth turns in 1 minute.
    there are 60 minutes in 1 degree.
    it just happens that this angle is very close to 1" at a distance of 100 yds
    so 1 moa = 1" at 100 yds, 2 moa = 2" at 100 yds, 3 moa = 3" at 300 yds.
    2 moa = 2" at 100 yds, 2 moa = 4" at 200 yds, 3 moa = 6" at 300 yds.
    1/2 moa = 1/2' at 100 yds, 1" at 200 yds, 1.5" at 300yds.
    measure group size in inches and divide by (range divided by 100) to get moa.
    e.g. you have just sot a 12" group at 500 yds.
    500 divided by 100 = 5
    12 divided by 5 = 2.4 moa.
    going into the mildot type scopes is confusing in this conversation other than to sy that moa type scopes are more useful to both hunters and target shooters due primarily to the fact that the adjustments on moa scopes are finer.
    milradians are suited to military where wounding is to be preferred to killing.
    bruce
     

  17. bruce moulds

    bruce moulds AH Elite

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    b.c. (ballistic coefficient) is a measure of slipperiness of a bullet through air relative to a standard bullet.
    the standard bullet in a g1 b.c. is different to the standard bullet in the g7 model.
    gi is used for flat base, and g7 for boat tails.
    the two come close in application, but not exactly the same when applied to a ballistic calculator like jbm calculations.
    suffice it to say that the higher the number, the more slippery is the bullet.
    more slippery means a lower percentage of muzzle velocity is lost due to drag, translating into less wind deflection.
    note the word deflection. there is no such thing as wind drift.
    if shooting longer ranges, high b.c. bullets are an advantage in the wind as well as retaining energy.
    one issue with high b.c. bullets is that many of them are suited more for target shooting and less for terminal performance.
    sometimes a compromise needs to be made here.
    s.d. ( standard deviation) is a form of statistical measurement.
    a mathematician can easily describe it better than me, but in essence it is a way of presenting an average value of a group of things.
    if you want consistency, the lower the s.d. the better.
    probably the 2 areas to most interest shooters are in weights and velocities.
    lower s.d in bullet weights, charge weights, case weights, etc. aid in ammunition consistency.
    the big one is velocity s.d.
    the lower this is, the pore shots in the sample will be nearer the verticle centre of the group.
    and probably the group in general as well, because the barrel is more likely to be nearer the same point in its oscillation as the bullet exits.
    some prefer to use extreme spread, e.s., rather than s.d.
    where this argument fails is that e.s. is a measure of 2 samples only, e.g. highest and lowest.
    s.d. is a measure of all samples and takes them all into account.
    bruce.
     

  18. bruce moulds

    bruce moulds AH Elite

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    please excuse multiple threads, but combining them could make it harder.
    shooting longer high b.c. bullets requires sufficient twist for stability.
    generally a gyroscopic stability (sG) of 1.5 is recommended, but at long range with long bullets going a little higher (say up to 1.8) can be of benefit.
    this is in part due to a thing called wind shear, when a bullet goes from one condition to another in its flight, be it wind speeds, directions or both.
    the changing forces on the bullet can cause it to wobble, enlarging the group.
    bruce.
     

  19. bruce moulds

    bruce moulds AH Elite

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    can't edit the post re b.c. and s.d.
    most things in shooting are statistical, rather than empirical.
    you need to take a lot of samples and compare them
    with s.d., say you are measuring velocities, s.d. is not meaningful for less than 10 shots, and more is better..
    bruce.
     

  20. Inline6

    Inline6 AH Veteran

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