Richards B.C

Discussion in 'Reloading' started by skeeter, Jul 2, 2005.

  1. skeeter

    skeeter Well-Known Member

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    How to you find out the BC on his bullets?
     
  2. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    Richard stopped offering predicted BC values for his bullets because awhile back there were some that basically called BS on these predictions.

    These predictions were actually offered by the die makers and Richard was only passing on this information in good faith and always listing them as predicted BC values.

    Because of that mess, Richard now lets us test them and figure out the BC values for ourself which in fact is the only real accurate way to do this anyway.

    Many will say this is to simplistic to be accurate but I simply use the known velocity of the load I am using and measure bullet drop at several different ranges. For moderate range usage I will get test drop data at 100, 300, 500 and 800 yards. For extreme range usage, I will get 500, 800, 1000 and 1300 yards if possible.

    Then I take this information and plug it into a ballistic program until the computer model matches the actual bullet trajectory but tweaking the BC value.

    While this may not be scientific enough for may, it gets me on small targets out to the one mile range very regularly so I will stick with the system.

    The only accurate way to get a certain bullets BC is to shoot them at the ranges you will be using them and see what they do.

    I will say I have yet to shoot a Wildcat bullet that did not produce a higher BC then any of the Sierra MK bullets and at times dramatically higher.

    What bullets are you interested in, I have tested several of his bullets and would give what data I have if it is what your looking for.

    Kirby Allen(50)
     

  3. skeeter

    skeeter Well-Known Member

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    Thanks kirby.
    Kirby can i get some info on your .270 Allen Mag.
     
  4. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    Skeeter,

    Here is a quick low down of the 270 Allen Mag. It is based on the full length 7mm RUM case with shoulder angle increased and body taper reduced to the Allen Magnum configuration.

    It was designed around the Rem 700 receiver and for use in 28-30" barrels of #5 to #7 contour for use on rifles that weigh in at 8.5 to 12 lbs and intended for serious deer and pronghorn hunting at extended ranges. Inital goals were to provide legit 600 yard performance but from the results we are getting, this round is an honest +1000 yard deer round.

    Performance wise, in a 30" pipe, your looking at a 130 gr bullet at 3850 fps, a 140 gr bullet at +3700 fps and best of the lot, the 169.5 gr ULD RBBT with its .750 BC right at 3400 fps with top loads.

    Recoil in my Extreme Sporters fitted with a Holland QD brake is about like a sporter weight 22-250 or 243 chambered rifle.

    With a solid shooting position, you can see every bullet land at any range.

    Dies are kept in stock to ship with rifles as are the Wildcat ULD RBBT bullets.
    Good Shooting!!

    Kirby Allen(50)
     
  5. big-foot

    big-foot Member

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    150-169-180-190 and the 200 gr. bonded .308s
    225-250-275 and the 300 gr. bonded .338s

    I thank you, and my information starved ballistic software thanks you.
     
  6. älg

    älg Well-Known Member

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    HI kirby, I don´t know what kind of facilities and equipoment you have, but do you have any measured - even aproximately- BC for the 6,5 wildcat bullets-?
     
  7. älg

    älg Well-Known Member

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    another thing, do you think testing with two crono´s would give accurate info for calculating BC based on velocity?
     
  8. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    I am putting together my 6.5mm Allen Mag test rifle, actually it is my wifes 1000 yard chuck rifle to be honest but it will also be my test platform for this wildcat. Anyway, as of yet I do not have alot of solid test data on the Wildcat 6.5mm bullets but it will be coming soon and I will post the results for you.

    I think two chronos are one of the best ways to get a true BC. Only problem is that it tells you the BC over the distance between the chronographs.

    100 yards is easy to do, 200 yards not to bad, 300 yards starts to get guys spooked pretty good and I know very few guys that will put their spendy chronographs up at 400 and 500 yard and try to shoot through the screens. In all honestly it can be done with the rifles and shooters on this board but its a mental thing!!! What if!

    Then for true long range BC figuring this is simply not practical. THis is why I use bullet drop to figure BC. Gravity is consistant no matter where you are, at least consistant enough to give you accurate data and when setting up the testing criteria you can get pretty good data and its very practical to do so.

    Collecting trajectory data from 100 yards, 300 yards, 500 yards and 800 yards will give you an extreme quality model of your trajectory that can then be applied to a ballistics program to fill in the holes so to speak.

    Good SHooting!!

    Kirby Allen(50)
     
  9. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    Big Foot,

    I have shot several of these bullet weights accuracy testing customers rifles but don;t have alot of BC data on them.

    I can tell you the 300 gr ULD RBBT "hunting" bullet has a BC in the .800-.810 range here at 3000 ft when driven from 2950 to 3050 fps.

    Sorry, not much help on the rest of them.

    Kirby Allen(50)
     
  10. älg

    älg Well-Known Member

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    thanks kirby. any specific program you use for those bc calc?
     
  11. älg

    älg Well-Known Member

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    thanks kirby. any specific program you use for those bc calc?

    By the way, congrats. on your cartridge family. you did not invent the allen keys also, did you ? /ubbthreads/images/graemlins/wink.gif
     
  12. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    Been playing with Load From A Disk lately. Pretty decent program but I think I will be getting Exbal on a handheld soon.

    Good shooting!!

    Kirby Allen(50)