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Flat base vs. boat tail for accuracy work

Discussion in 'General Reloading' started by Range Rat, Sep 10, 2011.

  1. Range Rat

    Range Rat G&G Newbie

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    It is my impression that most benchrest shooters at 100 and 200 yds go for flat-base bullets.

    For long range rifle shooting, such as at 600 yds, it will be all boat tails for obvious reasons.

    After three summers of experimenting with loads for my 22-250 varminter, I have found my best results with the 60 gr. Sierra HP varmint bullets. These are flat base, and are not even really target bullets at all. My shooting is at 100 and 200 yds, since the clubs I belong to do not have longer distances available. Groups with this bullet really shine.

    Am I the only one who thinks this?

    We are talking paper punching and small groups here. Hunting's an entirely different ball game.


     
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  2. Ten Man

    Ten Man G&G Evangelist

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    I have to agree with you, based on my experience with .308 loads.

    I found that the flat based Remington 165 grain PSPCL bullets (hunting bullets) were more accurate than the 165 grain Sierra SPBT bullets at 100 and 200 yards.

    I do not get the opportunity to shoot over 200 yards, except on rare occasions, so I have not been able to do a definitive test of these bullets at longer ranges.

    The one time I did shoot the flat based 165 grain PSPCL bullets at 625 yards, they held 1 MOA out of my 20" barreled AR10. I did not have any of the SPBT bullets loaded up for that shoot, so I could not compare them.
     
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  3. Gray Wolf

    Gray Wolf G&G Evangelist

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    There has to be a reason that the Sierra International Match BTHP bullets dominate the pack.
     
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  4. Slow Go

    Slow Go G&G Newbie

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    Your impression is correct but nothing in this game is a given for us until we've tried it in our own rig. Your rifle shoots best with what it likes best, hardly seems to matter if it's what others like or not. Fact is, statistically, flat bases do tend to shoot slightly better at supersonic speeds than boat tails. After the speed drops to subsonic that reverses. Usually.
     
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    Last edited: Sep 10, 2011
  5. Twitch2120

    Twitch2120 G&G Evangelist

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    boat tail bullets center the weight better. flat bases are butt heavy. shoot at longer distances and the flat base will bleed off speed faster because it has the tendency to nose up. boat tails also traverse the trans sonic zone much better. flat base bullets are more consistent lot to lot however and tend to group better at short distance. not sure the science involved
     
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  6. rockman7

    rockman7 G&G Evangelist

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    all things being equal (wieght, speed) the bt will/should do better with wind drift but won't be a variable until around 300+ yards.

    i do find bt's much easier to load with less signs of copper bein shaved off . and altho i don't shoot long range anymore (300-350 hunting ranges ) i use bt's soley for this reason. some spitzers shoot as well or better .... just a preferance that works for me
     
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  7. Bart B.

    Bart B. G&G Newbie

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    I disagree.

    Boattail bullets have less drag than comparable shape/weight flat base ones. Therefore, they don't slow down as fast.

    All bullets' spin axis is parallel to their trajectory. Both the nose and base centers are above the trajectory axis from muzzle to target.
     
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  8. Zapp Branigan

    Zapp Branigan G&G Newbie

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    Any difference in accuracy-velocity at different ranges
    IS INFINITESIMAL.
     
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  9. DaTeacha

    DaTeacha Things are not what they seem. Forum Contributor

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    I suggest a look at Steve's Pages as well as here: http://www.bordeninstitute.army.mil/published_volumes/conventional_warfare/chapter4/Pages1-12.pdf

    IMHO, the only reason I can see for flat base bullets working better than boattails at the shorter ranges might be a reflection of the consistency of the base. The comments about hypersonic and subsonic velocities make sense. I have to wonder about the effects of drag, length, pressure centers, etc.

    Personally, I very rarely get a chance for a shot over 200 yards so have never really had opportunity to notice any difference. My 22-250 like the 52 grain Sierra HPBT match bullet. My 6mm liked the 82 grain 6mm version of the same thing. Maybe it's just that I think "the bulletsmiths" do a good job with their boattails so have personal confidence in them.
     
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  10. Deersniper

    Deersniper G&G Newbie

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    With in common hunting ranges, the flat base will touch holes. 42 gr Varget / 150 Core Loclocts
    Boat tails are good in wind, and for targets at longer distances. I love 69 gr SMK for .223 with 25gr BLC-[2]
     
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  11. Bart B.

    Bart B. G&G Newbie

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    Sierra Bullets' has stated in their reloading manuals (and also on their web site, I think) that in their accuracy tests, flat base bullets tend to shoot more accurate in factory production barrels than boattails do. On the other hand, when custom match grade competition barrels were used, the boattail bullets shot most accurate.
     
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