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Thread: .375 Barnes Bullets BC Differences

  1. #1

    Default .375 Barnes Bullets BC Differences

    I would love to start working up some 270 and 300 grain TSX's for my 375 H&H, but am at a log jam. According to Midway, the BC's for these bullets are .503 & .555, yet on the Barnes reloading data site, it says they are .326 & .357. Which is correct?

    I am hoping the first - .270 TSX with a .503 BC loaded to 2800 fps would be a devistating long range thumper. It could shoot as flat and hit as hard as a accubond but with a tougher bullet.

  2. #2

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    BC of over .5 for Barnes TSX's sound very high. My guess is that there is a mis print on the Midway site. You can call Barnes to find out for sure.

    In a year or two Nosler should have some E-Tips for the 375 with good BC's

  3. #3

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    .326 and .357 are correct BC for the 375 Barnes TSX 270gr and 300gr. I shoot the 300gr TSX in my 375Wby and it groups tight out to 300yds. Have not tried it past 300yds.
    A GUN WRITER NEEDS:
    THE MIND OF A SCHOLAR
    THE HEART OF A CHILD
    THE HIDE OF A RHINOCEROS

  4. #4

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    In that case, I guess I am sticking with 260 accubonds. At 2800, they are as flat as a .270 150 grain, and hit like the fist of THOR

  5. #5

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    Quote Originally Posted by idahotrophyhunter View Post
    In that case, I guess I am sticking with 260 accubonds. At 2800, they are as flat as a .270 150 grain, and hit like the fist of THOR
    Yes, the 260gr Accubond is one fine bullet and is flat shooting. I would stick with it also especially if it has worked well for you.
    A GUN WRITER NEEDS:
    THE MIND OF A SCHOLAR
    THE HEART OF A CHILD
    THE HIDE OF A RHINOCEROS

  6. #6

    Talking midway's correct

    Quote Originally Posted by idahotrophyhunter View Post
    I would love to start working up some 270 and 300 grain TSX's for my 375 H&H, but am at a log jam. According to Midway, the BC's for these bullets are .503 & .555, yet on the Barnes reloading data site, it says they are .326 & .357. Which is correct?

    I am hoping the first - .270 TSX with a .503 BC loaded to 2800 fps would be a devistating long range thumper. It could shoot as flat and hit as hard as a accubond but with a tougher bullet.
    Idaho: According to the Barnes info I have, the .503 and .555 are correct. Makes sense they'd be high, because they're a longer bullet. Go with the tsx's and never look back. Good luck.
    If you like getting kicked by a mule...then you'll "love" shooting my .458.

  7. #7

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    Quote Originally Posted by Maydog View Post
    Idaho: According to the Barnes info I have, the .503 and .555 are correct. Makes sense they'd be high, because they're a longer bullet. Go with the tsx's and never look back. Good luck.
    The BC for the 375gr TSX's were corrected because there were other factors like the bands and the drag on the bullet that when they tested it they found that it was not .503 or .555. You might want to write Barnes and see what they have discovered about the TSX after testing.
    A GUN WRITER NEEDS:
    THE MIND OF A SCHOLAR
    THE HEART OF A CHILD
    THE HIDE OF A RHINOCEROS

  8. #8

    Talking really?

    Quote Originally Posted by beartooth View Post
    The BC for the 375gr TSX's were corrected because there were other factors like the bands and the drag on the bullet that when they tested it they found that it was not .503 or .555. You might want to write Barnes and see what they have discovered about the TSX after testing.
    Then, if that's the case, they'd have to refigure the complete line of TSX's wouldn't they? Maybe so...we'll see what Barnes has to say.
    If you like getting kicked by a mule...then you'll "love" shooting my .458.

  9. #9

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    I talked to a rep at Barnes today, and she didn't know the difference between her right and left hands....All she told me was to consult the load data and try back next week when someone would be in to answer my question...I WON'T be calling back.

  10. #10

    Default

    Quote Originally Posted by idahotrophyhunter View Post
    I talked to a rep at Barnes today, and she didn't know the difference between her right and left hands....All she told me was to consult the load data and try back next week when someone would be in to answer my question...I WON'T be calling back.
    Idaho, I have called Barnes on three ocassions and was put through to a knowledgeble tech each time who was able to answer my questions, including questions on ballistic cefficients... Not sure what you experienced but I never experienced that.

    You might give them another try.

  11. #11
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    Quote Originally Posted by Maydog View Post
    Idaho: According to the Barnes info I have, the .503 and .555 are correct. Makes sense they'd be high, because they're a longer bullet. Go with the tsx's and never look back. Good luck.

    Please tell me what length has to do with the calculations for Ballistic Coefficients. BC is always tied to Sectional Density. A .308" 180 grain bullet will have an SD of .27106

    (SD=weight in pounds divided by the square of the diameter.)

    The term Ballistic Coefficient is defined as the sectional density (SD) of the bullet and then compared to a standard bullet, or what is known as form factor. For the most part bullets were given a static BC mathmatically by comparing the SD to this form factor. This will vary with several factors. This form factor is somewhat greater than 1.000 and when it becomes the multiplier we get BC numbers a little greater than the SD number. (.217*1.124=.305)

    Bullet companies are now using very sophisticated measuring equipment to measure actual target end velocity at extended ranges, 600 to 1000 yards and obtaining much more realistic BC numbers. BC is then calculated backwards with known velocities rather than calculate down range velocities with not so valid BC numbers and attempt to correct errors. This research data is now being done by independent groups that are looking for more useful data and not trying to bolster their bullet sales numbers. Sierra and Barnes are two companies that have updated thier BC numbers recently. These two manuals will more realistically reflect true BC's.

    Also more and more is information is being gathered about the behavior of a bullet in flight, the effects of coning or precession of a bullet especially during the first 100 yards when this is more active (before the bullet goes to sleep). Also another factor is just the accuracy and dependability of better, more modern chronographing equipment.

    The BC of a bullet is different at different initial velocities and of course mean velocities over the path of travel. Also altitude and atmospheric conditions effect this number (temp, barometric pressure).

    When extreme long range precision is needed it becomes important. For a hunting rifle it really serves only for part of the mental exercise as we prepare for the hunt.
    Is there nothing so sacred on this earth that you aren't willing to kill or die for?



  12. #12

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    Quote Originally Posted by Maydog View Post
    Then, if that's the case, they'd have to refigure the complete line of TSX's wouldn't they? Maybe so...we'll see what Barnes has to say.
    Barnes has recomputed their BC's. Here's the link.

    http://www.barnesbullets.com/products/rifle/tsx-bullet/

  13. #13
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    Quote Originally Posted by idahotrophyhunter View Post
    In that case, I guess I am sticking with 260 accubonds. At 2800, they are as flat as a .270 150 grain, and hit like the fist of THOR

    It is really hard to beat that combo in the old H&H.
    Is there nothing so sacred on this earth that you aren't willing to kill or die for?



  14. #14

    Talking leave it to you Murphy

    Sorry for my lack of sophistication Murphy, but I've always had the impression that the longer a bullet was in relation to it's diameter, the higher the BC would be, as long as the shape was the same. Kinda like a 180 gr., .308 compared to a 165 gr., .308. You've undone a lifetime of theory, but that's why you're the professor...I'll quitely go to the corner and put on the hat. Thanks a lot. (But.....I'd still go with the TSX,s)
    If you like getting kicked by a mule...then you'll "love" shooting my .458.

  15. #15

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    Quote Originally Posted by Maydog View Post
    Sorry for my lack of sophistication Murphy, but I've always had the impression that the longer a bullet was in relation to it's diameter, the higher the BC would be, as long as the shape was the same. Kinda like a 180 gr., .308 compared to a 165 gr., .308. You've undone a lifetime of theory, but that's why you're the professor...I'll quitely go to the corner and put on the hat. Thanks a lot. (But.....I'd still go with the TSX,s)
    +1 Absolutely I would also go with the TSX. I shoot out to 300yds with a 300gr TSX and it is highly accurate in my 375Wby but more important is that the bullets ability to open up at close range but stay in tack and makes devastating wound channels and will still open up at longer ranges. I have not use the .375Wby on game yet but can only imagine what it will do. I have shot big boar with the 180gr TSX up close and at distance and the wound channel was something to see and I can just imagine what a 270gr or 300gr TSX will do on a brown bear, moose or Elk.
    A GUN WRITER NEEDS:
    THE MIND OF A SCHOLAR
    THE HEART OF A CHILD
    THE HIDE OF A RHINOCEROS

  16. #16

    Talking

    Quote Originally Posted by beartooth View Post
    +1 Absolutely I would also go with the TSX. I shoot out to 300yds with a 300gr TSX and it is highly accurate in my 375Wby but more important is that the bullets ability to open up at close range but stay in tack and makes devastating wound channels and will still open up at longer ranges. I have not use the .375Wby on game yet but can only imagine what it will do. I have shot big boar with the 180gr TSX up close and at distance and the wound channel was something to see and I can just imagine what a 270gr or 300gr TSX will do on a brown bear, moose or Elk.
    Hi BT: I agree about the tremendous wound channels, but I find that there isn't as much meat damage (or hydraulic damage) with the larger Barnes as with the smaller weights. Probably because of a little slower velocity. My .458, 350 gr Barnes X would have a great wound channel, but shock damage was so so. Then I went to the 300gr Barnes X...have mercy. Great wound channel, but tremendous shock damage. Not good for a shoulder shot and edible meat. Both will still shoot thru large buffalo, so I guess they'll take care of anything else I'll go after. Also, their BC's suck, but doesn't matter to 250 yds. To many other factors go into this hunting...I think BC is only one small part.
    If you like getting kicked by a mule...then you'll "love" shooting my .458.

  17. #17
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    Quote Originally Posted by Maydog View Post
    Sorry for my lack of sophistication Murphy, but I've always had the impression that the longer a bullet was in relation to it's diameter, the higher the BC would be, as long as the shape was the same. Kinda like a 180 gr., .308 compared to a 165 gr., .308. You've undone a lifetime of theory, but that's why you're the professor...I'll quitely go to the corner and put on the hat. Thanks a lot. (But.....I'd still go with the TSX,s)
    Sorry to unravel things but much of what we apply (of physics) to bullets is based on certain facts that are changing. Take for example twist rate calculations from the Greenhill Formula. This based on lead bullets treveling in the atmosphere, with certain atmospheric attributes. The atmosphere can change and have some effect but making bullets from substances other than lead (which we see a lot of today) can make a big difference. The length of the projectile is a factor in twist rate needed to stabilize a bullet. If we use pure lead for a 180 grain, .308 diamter bullet the fomula works well, but if we use aluminum for the bullet, a 180 grain 308 will be a foot long and it cannot stabilize with a standard 1 in 10 or 1 in 12 twist. If we alloy this lead with tin or antimony or wrap it in copper, it changes things but so slight that it isn't an issue. Bullets made of pure copper on the other hand are significantly lighter than lead and will be longer by about 20% when of the same shape, caliber and weight. Twist rate needs should be re-evaluated. Sierra has 240 grain SBT of .308" diameter, they recommend a twist of 1 in 9". Barnes has a 200 grain .308" SBT and they recommend a twist of 1 in 9" for that one. Both are correct, but the 200 grain SBT Sierra doesn't need a 1 in 9" twist and Sierra doesn't suggest it.

    So many folks are under the impression that longer bullets have better BC but BC is a term used to indicate how well a bullet maintains its velocity over distance. It looses velocity from air resistance, reducing its air resistance is done by makeing it slicker or more streamlined. Momentum is the component that pushes the bullet through the air. (Mass in motion) This quantity is a product of mass and velocity. Nothing else is in the formula. SD gives us the bullets weight vs its cross sectional area (d^2) which is the main factor of air resistance, the form factor tells us how much better the bullet will fly compared to one shaped like a 55 gallon oil drum. That's why BC is always a greater number than SD, unless it is shaped like a 55 gallon oil drum (i.e. 38 spcl 148 grain WC).

    A heavier for caliber bullet will be longer but certainly the shape of a 150, 180, or 240 grain .308" bullet could all be the same, just the mass in motion will be greater, therefore the SD and BC numbers will be greater, for the heavier bullets. Yes the greater SD/BC bullet will be longer but that isn't the reason for the higher numbers. If we change to a lighter weight substance to make the bullet it will be longer for a given weight/caliber but if in keeping with the same shape, it's BC willl be the same. Now the reality of it is that given the same seven caliber secant ogive, a longer bullet cannot have the same shape as a shorter bullet. Oh it will be the same general shape, but we cannot maintain the same ogival configuration for a bullet once it's length reaches a certain point. The bearing surface of the bullet will not be enough to give enough contact to spin the bullet, so we change the shape to a tangental ogive or a different radius arc to calculate the nose profile (5 caliber or nine caliber, etc.)

    I cannot speak to the most aerodynamically efficient bullet, one made of copper may or may not be better because of the length/ogive, etc but to say that a longer bullet has a higher BC is erroneous thinking. I think bullet makers are just very recently listing more accurate BC numbers for all their bullets and this comes from better range testing because of better equipment. Sierra listed one of the possible errors for some of their BC's on a 3&3/4" error in distance over the 100 yard range where they measured the down range velocity. They must be pretty conscienciously working to improving their BC numbers.
    Is there nothing so sacred on this earth that you aren't willing to kill or die for?



  18. #18

    Default I shoot the 270

    tsx through my .375 ultra mag. They are awesome! Extremely good shooting through my rifle. I don't shoot any other bullet in my guns but the tsx.

  19. #19
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    Quote Originally Posted by northway View Post
    tsx through my .375 ultra mag. They are awesome! Extremely good shooting through my rifle. I don't shoot any other bullet in my guns but the tsx.
    What did you shoot in your gun before the TXS was invented?
    Is there nothing so sacred on this earth that you aren't willing to kill or die for?



  20. #20

    Talking Huh?

    OK Murphy: I get what you're saying and it straightened me out. Now, next question is that if some bullet makers are becoming more accurate with an updated system of measuring, then it seems as though that all must follow because all bullets will need updating, right? When that happens, then everything should be back in sync. We'll just be seeing somewhat lower numbers, but more accurate. Correct? I just feel we make to much out of BC numbers, unless we're 1000yd Penna Benchresters.
    If you like getting kicked by a mule...then you'll "love" shooting my .458.

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