Welcome guest, is this your first visit? Create Account now to join.
  • Login:

Welcome to the NZ Hunting and Shooting Forums.

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed.

Alpine Darkness


User Tag List

+ Reply to Thread
Results 1 to 11 of 11
Like Tree15Likes
  • 1 Post By PaulNZ
  • 1 Post By Micky Duck
  • 1 Post By Husky1600#2
  • 2 Post By STC
  • 1 Post By Micky Duck
  • 3 Post By -BW-
  • 3 Post By Beetroot
  • 3 Post By Marty Henry

Thread: Boat tails v.s. flat base projectiles

  1. #1
    Member
    Join Date
    May 2025
    Location
    Auckland
    Posts
    1

    Boat tails v.s. flat base projectiles

    My 243 groups better with flat base projectiles than with boat tails, and Ive seen someone else say the same on a US hunting forum. Any thoughts on why that could be?

  2. #2
    Member PaulNZ's Avatar
    Join Date
    Sep 2016
    Location
    Waikato
    Posts
    458
    Flat base projectiles are less sensitive to an less-than-perfect barrel crown, is one theory I've heard. Makes some sense to me but I've never tried to prove it.
    Warthog likes this.

  3. #3
    Member Micky Duck's Avatar
    Join Date
    Apr 2015
    Location
    Geraldine
    Posts
    25,565
    They fly shit shorter....can fill a worn bore better,the moon was in correct alignment when made. Just go with it. Boattails are easier to load as sit nicely in case to start seating but other than that tiny quirk ,I have never seen advantage....but I don't shoot long range either.
    Warthog likes this.
    75/15/10 black powder matters

  4. #4
    Member
    Join Date
    Mar 2023
    Location
    Central South Island
    Posts
    645
    Some of mine prefer FB as opposed to BT. Is common with BSA's.
    Warthog likes this.

  5. #5
    STC
    STC is online now
    Member
    Join Date
    May 2023
    Location
    South
    Posts
    820
    Different projectiles... different harmonics.

    Some guns just like some combinations.

    I.e. your gun might like a different boat tail projectile better still, or different powder... etc...

    Not necessarily boat tail vs flat base.
    Eat Meater and Warthog like this.

  6. #6
    Member Micky Duck's Avatar
    Join Date
    Apr 2015
    Location
    Geraldine
    Posts
    25,565
    Quote Originally Posted by Husky1600#2 View Post
    Some of mine prefer FB as opposed to BT. Is common with BSA's.
    Think older slightly worn bores....may find Speer projectiles go very well in it for same reasons...they squish out to fill grooves better perhaps.
    Warthog likes this.
    75/15/10 black powder matters

  7. #7
    Member -BW-'s Avatar
    Join Date
    Jun 2019
    Location
    Shannon
    Posts
    1,182
    The theory is that a boat tail in certain bores may allow propellent gases to flow past the base, decreasing obturation of the projectile in the bore, and potentially allowing these gases to exit around the projectile at the muzzle unevenly, thus upsetting accuracy. By comparison, the flat surface area of the flat base, holds back more of the propellant gas, which pushes against this larger flat area, causing better obturation and sealing the gases behind the projectile.
    Or something like that...

  8. #8
    Member
    Join Date
    Mar 2013
    Location
    Bell Block NZ/Northern Alberta Canada
    Posts
    1,164
    Over the Year's, I have found flat base easier, to get to shoot well, with several powders and OAL, Boat tails, seamed to require a bit more tuning, always exceptions, but all the best target bullets, in my 3, 6mm PPC, were flat base.
    good old soft point, flat base for bush work, Boattail for way out there.

  9. #9
    Member Beetroot's Avatar
    Join Date
    Apr 2013
    Location
    Waikato
    Posts
    3,197
    Flat base bullets are typically easier to find accuracy for but have a lower BC so not as good at long range.
    If you are shooting inside of 300m then it probably doesn't matter.

    If you tell us what your ammo is or the bullet + velocity, can easily plug into a ballistic calculator and see if it's worth wasting time on boat tail bullets for your use.

    It's actually more complicated than flat base vs boat tail, it comes down to bearing surfaces length, boat tail length, ogive shape, basically the better the bullet is aerodynamically the more sensitive it is to twist rate and seating depth.
    The newer TMKs, SMKs, ELD-M/X, Berger Hybrids do a good job of making a high BC bullet that is easier to find accuracy with.

  10. #10
    Member
    Join Date
    Jun 2019
    Location
    Manawatu
    Posts
    1,220
    Most 243s are slow twist so shoot shorter bullets better. Boat tail bullets are usually longer so need a faster twist rate.

  11. #11
    Member Marty Henry's Avatar
    Join Date
    Oct 2014
    Location
    Tararua
    Posts
    7,338
    Quote Originally Posted by -BW- View Post
    The theory is that a boat tail in certain bores may allow propellent gases to flow past the base, decreasing obturation of the projectile in the bore, and potentially allowing these gases to exit around the projectile at the muzzle unevenly, thus upsetting accuracy. By comparison, the flat surface area of the flat base, holds back more of the propellant gas, which pushes against this larger flat area, causing better obturation and sealing the gases behind the projectile.
    Or something like that...
    And the proof of what -BW- said is in writing and pictures. This is from an early Lyman reloading guide from a time of white shirts thin black ties, black rimmed glasses, pocket pen protectors, slide rules and right clever bastards.
    Attached Images Attached Images  
    Ruger7mm, Huk and Grasshoppa like this.

 

 

Similar Threads

  1. Sierra Spitzer Boat Tails
    By RugerM77 in forum Reloading and Ballistics
    Replies: 4
    Last Post: 19-05-2022, 08:59 PM
  2. Looking for 6mm/243 projectiles, preferably flat base spitzer
    By cbfb in forum Projectile and Factory Ammo Exchange
    Replies: 9
    Last Post: 03-02-2022, 02:05 PM
  3. Flat base .308
    By WillB in forum Reloading and Ballistics
    Replies: 21
    Last Post: 16-11-2018, 02:17 PM

Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
Welcome to NZ Hunting and Shooting Forums! We see you're new here, or arn't logged in. Create an account, and Login for full access including our FREE BUY and SELL section Register NOW!!