Roy, I have some bc's.........

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by goodgrouper, Apr 7, 2006.

  1. goodgrouper

    goodgrouper Well-Known Member

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    Roy, I have some bc\'s.........

    Ok, tested the .338 250 gr MK, the 252 Wildcat RBBT, and the 250 grain Lapua scenars today.

    Temp was 59, elevation 4888, humidity 60%, baro 29.82, and no wind. All loads were loaded with 90.2 grains of RL22.

    The Oehler 35 was set up 10 feet from the muzzle and a shooter chrony just after the Oehler. 3 test bullets were fired in this manner to see how close the chrono's were reading. Taking averages, we determined the Chrony was reading 17.3 fps faster than the Oehler.

    Then we moved the Chrony out to the exact 100 yard mark and shot the bullets.

    <font color="blue"> The Scenars avged 3084 muzzle and 2960 at 100 yards for a total slow down of 124 fps. This equates to a bc of .667 average. </font>


    <font color="red"> The 250 MK's averaged 3040 at the muzzle and 2906 at 100 yards for a loss of 134 fps which equates to a bc of .610 (just like I guessed last week!) </font>



    <font color="green"> The 252 RBBT wildcats clocked 3020 average at the muzzle and 2868 at 100 yards for a slowdown of 152 fps for a bc of .534. </font>


    So, the Scenars are advertised right on for bc. The MK's are rated quite conservatively at .587, and the Wildcats were less than expected.

    There's the straight poop with no sugar coating! Hope it helps with your decision making. /ubbthreads/images/graemlins/wink.gif

    Oh, and BTW, the MK's put them in the same hole at 100!
     
  2. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    Re: Roy, I have some bc\'s.........

    GG,

    Were those the 252 gr ULD RBBTs with the lead right to the tip and a wide meplat? I have some of these as well and suspect the wide meplat is the reason for the lower then expected BC. These are big game bullets, not match bullets like the other two you tested, so for that use, its a pretty decent BC.

    Good information!!

    Kirby Allen(50)
     

  3. royinidaho

    royinidaho Writers Guild

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    Re: Roy, I have some bc\'s.........

    GG,

    Good deal. That'll save some shooting &amp; guessing on my end. It's about what I expected. But I had no way of getting a starting measurement.

    Are there any other things that you can do for me? /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif

    Kirby:
    Yep, those are the ones. The tip has slightly greater angle than the ogive and lead goes to the tip.

    With the way they shot in my Win, a bc on that order, the RUM velocities with the new bbl and the anticipated terminal performance I see no problem whatever being able to make a clean 'harvest' across the canyon....
     
  4. davewilson

    davewilson Well-Known Member

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    Re: Roy, I have some bc\'s.........

    GG, i'm kinda curious about the chrony. it was a little faster but how consistant was it?
     
  5. Meister

    Meister Well-Known Member

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    Re: Roy, I have some bc\'s.........

    I've been considering the wildcat bullets, but with no BC data I was hesitant to buy a batch. Any way you could throw some more wilcats of different weights in 338 caliber thru those chrono's? I only have axcess to 1 myself, otherwise I would do the same. Thanks
     
  6. goodgrouper

    goodgrouper Well-Known Member

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    Re: Roy, I have some bc\'s.........

    [ QUOTE ]
    These are big game bullets, not match bullets like the other two you tested, so for that use, its a pretty decent BC.

    [/ QUOTE ]


    True. But the 225 accubond is roughly the same bc and it will go faster.
     
  7. goodgrouper

    goodgrouper Well-Known Member

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    Re: Roy, I have some bc\'s.........

    [ QUOTE ]
    Are there any other things that you can do for me?


    [/ QUOTE ]

    Well, just name it!

    BTW, I tested some more 250 MK's that I bought today and they came out at .615 so it seems to be pretty close to your lot. Good bullets.
     
  8. goodgrouper

    goodgrouper Well-Known Member

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    Re: Roy, I have some bc\'s.........

    Dave,

    Every bullet that was faster on the Oehler was faster on the Chrony as well. It fluttered a bit on a couple bullets but was ok yesterday. Today, it was a bit more finicky with where the sun was in relation to the lenses. The Oehler 35....no problems ever. /ubbthreads/images/graemlins/wink.gif
     
  9. goodgrouper

    goodgrouper Well-Known Member

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    Re: Roy, I have some bc\'s.........

    If you can get me the bullets, I will test a few for you. Or, if you want to pay the shipping, I'll send you the Chrony so you can test the bc's out of your own rifle because that will change them a bit.
     
  10. Meister

    Meister Well-Known Member

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    Re: Roy, I have some bc\'s.........

    Sounds like I need to get a 35. My chrony seems to hiccup too. Thanks for the offer.
     
  11. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    Re: Roy, I have some bc\'s.........

    GG,

    Not disputing your numbers at all, I just want everyone to realize what we are comparing here as far as bullet design. Both the SMK and Scenar are true match bullets with very tight meplats. The Accubond, with its tipped nose has the finest and most consistant nose of them all.

    The 252 gr ULD RBBT Wildcat Bullet on the other hand is a big game bullet design so the meplats are totally different and this needs to be realized and understood.

    [​IMG]

    The bullet on the left is a 300 gr ULD RBBT Wildcat. The one on the right is the 252 gr ULD RBBT with its very broad meplat and lead to the tip design.

    [​IMG]

    Another pic of the same two bullets. The 252 gr ULD RBBT has a meplat similiar to that of a Swift A-Frame to be honest. It is designed mainly for expansion performance on game more then ballistic properties.

    The Meplat in the 300 gr ULD RBBT is similiar to the SMK but not as tight I believe as the Scenar bullet.

    Again, not questioning any BC numbers. I am sure they are on the money but just wanted to clearify to those reading this post what exactly is being compared visually. May make the numbers a bit easier to understand for those that have not handled these bullets.

    Again, just offering pics not questioning the results.

    Kirby Allen(50)
     
  12. jwp475

    jwp475 Well-Known Member

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    Re: Roy, I have some bc\'s.........

    When I order Wildcat bullets from Richard he asked if I expected any close shots and if so recomended the bullet with the lead to the tip, if only long shots then then smaller meplat would be the choice.Give up a little bc for better wieght retension at close range
     
  13. goodgrouper

    goodgrouper Well-Known Member

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    Re: Roy, I have some bc\'s.........

    Absolutely.
    Thanks for the pictures. That is what they looked like alright.

    Tell us Kirby, what does Richard make for hunting and match bullets in the 225-250 weight class and what are the jackets made from? His website shows a few 338's but I couldn't even find the 252 RBBT on there so I gather that there are more bullets produced than what is on his site.
    Thanks.
     
  14. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    Re: Roy, I have some bc\'s.........

    GG,

    Well, Richard offer 200, 225 and 250 gr that can be had with either a #6 or ULD ogive and as either Flat base or RBBT.

    In his bonded core bullets he lists 200, 210, 215, 225 and 250 gr. All of these are flat base and can be had with either a #6 or ULD ogive.

    I am not sure on the jacket maker for the 338 bullets but he offers 0.030", 0.040" and 0.065" thicknesses on his bullets.

    Anything thicker then the 0.030" jackets will have limited expansion, especially at longer ranges. These are as heavy as I personally would use on thin skinned game at long range.

    Richard is very creative. If you have a bullet weight in mind he will generally work with you to a point.

    I believe the 252 gr ULD RBBTs are basically the 250 gr ULD RBBT but with the lead filled to the tip and a broader meplat to promote mushrooming better then the tight match meplats.

    Kirby Allen(50)