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Thread: chronograph reality!!!!!!!

  1. #1

    Default chronograph reality!!!!!!!

    I dropped my Chronograph the first of Dec. and thought I broke it. So I put it back on the tripod and shot a few rounds and did not pay attention to the exact numbers that came up, but just glad to see numbers. Every since then I have had above average velocity recordings. Well some of you have questioned my velocity numbers and even have me doubting or wondering myself. So I ordered a new Chronograph and I will be able to compare my 257-300Wby and my 350 Rem mag. This ought to be interesting. I decided to do this when I fired my 22-250 last week and with factory loads recorded 175fps above what I use to get and my handload was 207fps above my average. This should be interesting.

    Well, I went to the range this morning and boy was I ever enlightened by the results. Of course I did as Smokin advised me to and lined them up in a row. Well the old chrono was well above the new chrono in velocity. I stood there looking at them wondering why is this happening???? As I looked at both of them in a row I saw it and it jumped right out at me, why had I not noticed it before. Having them both in a row caused me to notice that the old chrono was not folded out flat like the new one. So I took it off the tripod and where I had dropped it in December it had bent the sheet metal just on the end that you fold down and was not allowing the chrono to completely open up an lay flat. This meant that the rear photo cell was pointing in a slight angle toward the front photo cell and this shortened the distance between the two. That means the old chrono was recording the speed over a shorter distance that it was not calibrated for so the speeds were faster. Here are the real results of my 257-300Wby with 2 grains below max load for my rifle and also my 350 Rem Mag. at 2 grains below max load.


    Average 86grs Retumbo 100gr TSX


    Accuracy of the load which was outstanding


    RL-25 average at 2grs below max 100gr TSX


    Average for 350 Rem Mag 225gr Sierra


    Well now we know why I was getting such high velocities and also know what the truth is. I think I will stay with the 3850fps because the accuracy was so good. With the 350 Rem Mag I will try 61.5grs of WW748 and see what happens.
    A GUN WRITER NEEDS:
    THE MIND OF A SCHOLAR
    THE HEART OF A CHILD
    THE HIDE OF A RHINOCEROS

  2. #2

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    I know some speed dreamers that would pay a premium for your damaged chrono!

    Good job sorting it all out.

  3. #3

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    Quote Originally Posted by BrownBear View Post
    I know some speed dreamers that would pay a premium for your damaged chrono!

    Good job sorting it all out.
    Thanks BrownBear, I have bent it back and it looks like it is folded all the way flat now. I am going to give it to my grandson and teach him how to load and keep record of this stuff. He will have a ball seeing his 22-250 velocities after his shots.
    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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    Good job on that little problem. That also is a good endorsement for that brand of chrony. That's a good lesson and when you get the old one recalibrated, put it down at the 100 yard line, or 200 if you dare, and we'll calculate BC of the bullets. Nothing wrong with having two. I have two but they are in two different states.
    Is there nothing so sacred on this earth that you aren't willing to kill or die for?



  5. #5

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    Quote Originally Posted by Murphy View Post
    Good job on that little problem. That also is a good endorsement for that brand of chrony. That's a good lesson and when you get the old one recalibrated, put it down at the 100 yard line, or 200 if you dare, and we'll calculate BC of the bullets. Nothing wrong with having two. I have two but they are in two different states.
    Yea a little problem solving only teaches good lessons and bring good results. Yes, that is one fine group and 3850fps is not shabby for a 100gr TSX by any stretch of the imagination. This will be a flat shooting, hard hitting up close or far off round with the TSX at these velocities.
    A GUN WRITER NEEDS:
    THE MIND OF A SCHOLAR
    THE HEART OF A CHILD
    THE HIDE OF A RHINOCEROS

  6. #6

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    With this 86grs Retumbo load moving a 100gr TSX at 3850fps and with only a sight-in of 2" high at 100yds - gives the following potential for this deer and small to medium black bear killing round. I know I will have to actually try it at the range but the following gives an idea of potential for this cartridge with this load.

    Trajectory
    100yds +2"
    200yds +2.85"
    300yds +0.44"
    400yds -5.74
    Hold on top shoulders at 425yds and good out to 500yds

    Energy
    Muzzle 3290.7
    100yds 2817.3
    200yds 2408.2
    300yds 2053.3
    400yds 1744.2
    500yds 1474
    Not bad at all for a 100gr bullet
    A GUN WRITER NEEDS:
    THE MIND OF A SCHOLAR
    THE HEART OF A CHILD
    THE HIDE OF A RHINOCEROS

  7. #7
    Member Float Pilot's Avatar
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    I have an old Chrony, (that I once shot witha 38 special but put back together) and an old Ohler 33. The Ohler has 3 or 4 feet between the screens, that are mounted in a 1x6. So I just put the chrony in between the Ohlers screens and get two readings from every shot. They are always a touch different, but I just reviewed my loading log book and they are usually within 20 fps of each other on average.
    Floatplane,Tailwheel and Firearms Instructor- Dragonfly Aero
    Experimental Hand-Loader, NRA Life Member
    http://site.dragonflyaero.com

  8. #8

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    Quote Originally Posted by Float Pilot View Post
    I have an old Chrony, (that I once shot witha 38 special but put back together) and an old Ohler 33. The Ohler has 3 or 4 feet between the screens, that are mounted in a 1x6. So I just put the chrony in between the Ohlers screens and get two readings from every shot. They are always a touch different, but I just reviewed my loading log book and they are usually within 20 fps of each other on average.
    WOW Float Pilot, 3 or 4 feet between screens and that is cool what you do with the chrony in between.
    A GUN WRITER NEEDS:
    THE MIND OF A SCHOLAR
    THE HEART OF A CHILD
    THE HIDE OF A RHINOCEROS

  9. #9
    Member Big Al's Avatar
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    Quote Originally Posted by Murphy View Post
    Good job on that little problem. That also is a good endorsement for that brand of chrony. That's a good lesson and when you get the old one recalibrated, put it down at the 100 yard line, or 200 if you dare, and we'll calculate BC of the bullets. Nothing wrong with having two. I have two but they are in two different states.

    Sounds like you do some long range shooting, Murphy. What is the other state you are shooting at?
    "The tree of liberty must be refreshed from time to time with the blood of patriots and tryants." (Thomas Jefferson

  10. #10

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    What kind of exaggerated BC is Randy quoting for this bullet?

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