Is a Boat Tail worth its Salt?

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by royinidaho, Oct 30, 2008.

  1. royinidaho

    royinidaho Writers Guild

    Messages:
    8,853
    Joined:
    Jan 20, 2004
    Just how much advantage is a boat tail over a flat base on two bullets that are exactly the same except for the boat tail.

    I'm talking to 1200 yards.

    On exceptionally long bullets is the longer bearing surface of the flat base have a major effect.

    I'm talking 170gr 277 cal bullets.

    I have some 170 grain double jacketed bronze tip flat base bullets coming one of these days for testing.

    The inner jacket is a lead core "wadcutter" design. the outer jacket is high bc design w/bronze point.

    Any hintz?
     
  2. Derek M.

    Derek M. Well-Known Member

    Messages:
    2,417
    Joined:
    Jul 12, 2004
    I spoke with Sierra and Speer about this many years ago. They both gave the same answer:

    "Inside of 300 yards, take your pick. In fact, the flat base spitzer will likely be more accurate because there is little to no deformation of the bullet base, so when the gas pushes the bullet out the muzzle, it is more even. That is the trick with a boat tail bullet and seating. The less concentric a boat tail is seated, the higher the risk of uneven gas blow by. However, long range accuracy ultimately means using Boat tails with high BCs."
     

  3. royinidaho

    royinidaho Writers Guild

    Messages:
    8,853
    Joined:
    Jan 20, 2004
    Derek,

    Thanks for the response.

    To be more specific, lets consider the Sierra 300 SMK.

    How much lower for BC if it were a flat base?
     
  4. Mikecr

    Mikecr Well-Known Member

    Messages:
    4,264
    Joined:
    Aug 10, 2003
    It would be a big difference in a 300smk(~.1 in BC). And anyone shooting 1200yds for some reason, should consider the increase in wind drift(especially your error) from this.

    Nothing is free
     
  5. royinidaho

    royinidaho Writers Guild

    Messages:
    8,853
    Joined:
    Jan 20, 2004
    Mikecr,

    That much eh? Wouldn't hat tho't it.

    my problem is I'm shooting 140gr 277 bullets w/a .496 BC @3600 FPS.

    A 170 class bullet w/a bc of 0.74 @ 3250 will out do the faster 140 class bullet at any distance all the way around.

    However the 170 class bullets are no longer available.

    But I've found a maker producing very similar bullets to the aforementioned 170 class bullet. Its better up front in that it has a bronze point vs a hollow point. On the back end it is flat based vs RBBT.

    I'm not looking for a free lunch, just somewhat of a feeling for what's going on before I jump in.

    Found this link:http://www.longrangehunting.com/forums/f17/flat-base-versus-boat-tail-789/
     
    Last edited: Oct 30, 2008
  6. Derek M.

    Derek M. Well-Known Member

    Messages:
    2,417
    Joined:
    Jul 12, 2004
    Which 170 bullet is no longer available?
     
  7. James Jones

    James Jones Well-Known Member

    Messages:
    2,854
    Joined:
    Jul 1, 2002
    it all boils down to BC , if you could get a flat base bullet to have a well enough desgine at 170grs to match the BC of the old 170gr bullet that it should shoot pretty close but in order to gain that BS without the sleek boat tail the ogive is gonna be Loong so it may be hard to get to shoot well.

    If you look at the short range BR guys the vast majority of them shoot flat base bullets but any of them shooting to 600 or more generaly always shoot the boat tails.

    That sounds like a very expensive bullet to produce your looking at , you may want to try out some of the Lathe turned bullets out their though your barrel may not like them
     
  8. BountyHunter

    BountyHunter Writers Guild

    Messages:
    4,803
    Joined:
    Jun 13, 2007
    There is a pretty good contingent of LR shooters shooting the Knight and BIB flat base bullets for 1000. I shoot the BIB 187 FB bullet in a 300 WSM with 12 twist. Lot of guys are using the 300 Ack Imp and 12, 13 or even 14 twists with the 187 BIB and up around 3300 fps.

    The major reason is that it is much easier for the custom bullet maker to make a very good FB bullet compared to the BT. We take the normal BT sort by weight, ogive and then some run them over a Juenke machine to sort further.

    BIBs, I take them out of the box and shoot, they are that much better quality wise.

    Now we give up a good bit of BC, but in a known distance game that is not an issue and quality bullets mean more.

    The BIBs use a pressure ring on the base and that must be in the neck. That means the chamber must have an extra long throat and 210s will not even come close to touching in my chamber and it makes it a one bullet gun.

    Bottom line is that for LR hunting, you will want the BT normally due to the extra BC.

    BH
     
  9. royinidaho

    royinidaho Writers Guild

    Messages:
    8,853
    Joined:
    Jan 20, 2004
    Wildcats..........

    JamesJones,

    Bullets are for harvesting out of a 270 AM.

    The bullets are expensive, but at $2.00 each it isn't out of line at all if they shoot well, have a sufficient BC for 1200 and are only shot at elk and moose.

    The 150 Nosler Ballistic Tips shoot better at distance compared to the 140 NABs each with the same bc which is much lower than any decently designed 170 class 277 bullet.

    The wildcat 169.5s are right at 0.74 out of my barrel at 3300 and at 4480' elevation.

    If a flat base bullet of similar design is even a 0.6 bc and velocity is not limited by the bearing surface, it should be a go. Wouldn't ya think?

    The 150 Bergers are very unstable above 3200 out of my rifle thus they aren't among those selected.....

    Maybe if Kirby gets that new fangled throat design finalized then I may be able to go back to the 195 wildcat which I have some of......
     
  10. RockZ

    RockZ Well-Known Member

    Messages:
    899
    Joined:
    Mar 10, 2006
    I shoot the 95gr BIB FB out of my 6Br and they are awesome shooters. The best bullet I have shot out to 600yds in my rifle. Randy makes very consistent bullets.
     
  11. srhaggerty

    srhaggerty Well-Known Member

    Messages:
    565
    Joined:
    Oct 12, 2004
    Roy,

    So is Wildcat bullets no more or just the 169.5's?
     
  12. MagMan

    MagMan Well-Known Member

    Messages:
    1,008
    Joined:
    Dec 20, 2002
    Roy, $2.00 a whack seems plenty steep for me. I don't care how good they are. In my eyes there is a fine line between cost and performance.
     
  13. royinidaho

    royinidaho Writers Guild

    Messages:
    8,853
    Joined:
    Jan 20, 2004
    As far as I can gather the whole thing is kaput.......

    I've been reduced to shooting 140 NABs........ which pretty much makes the AM to big for little work and too little for big work.

    Word from Eric @ Berger says that work on a heavy 277 has commenced and is about a year behind the 338 soon to be offering.
     
  14. goodgrouper

    goodgrouper Well-Known Member

    Messages:
    2,705
    Joined:
    Sep 3, 2004
    In a word, yes.

    I've even switched over to boat tails in short range benchrest. They load easier, they do have higher bc's, and if they shoot just as accurate, why not?