needing to learn about crony results

Forums Springers, Pumpers, C02, & Replicas needing to learn about crony results

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    OldFartFarmer
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    sorry to be a pest, and show my stupidity,

    Ive got a HW97kt .22 and have borrowed my friends caldwell chronograph, an have it hooked up to my Note-8,

    it gives me FPS readings,

    but not FT-LBS

    I have 8 diffrent type weight and brand pellets,

    Im shooting inside,( because im and oldfart-sissy and I aint going out in the cold,)

    at 18ft

    every pellet in a 5 shot group can be covered with a dime, some when i do my part are almost a hole in one,

    when I use the crony what am i looking for?

    what should it be telling me?

    is there a secret number? or FPS im looking for?

    thank you for taking the time to further my edumacation in the pellet world

    cheers

    John

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    AirNGasman
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    The chronograph displays velocity; you'll have to calculate energy.

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    JW652
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       Don't know the software. But you can back to the 20th century. Go and look at the screen on the front of the chronograph. There should be a button that will summarize string results – ave velocity; fpe; extreme spread; standard deviation. Or use the simple formula for energy:  pellet weight x V x V x .000002221. Back to the future!

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    intenseaty22
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    https://www.airgunsofarizona.com/Calcs.html

    John, nothing to be sorry about, we all learned one day from scratch. Write down your velocities, specifically the average velocity. Plug in the numbers in the correct calculator above. Pellet weight and speed to get Foot Pound Energy. 

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    brian_null
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    The "Magic Number" is 671… at 671fps the pellet weight in grains equals the foot pounds of energy. (slower = less, faster = more)

    (example) If you shoot a 18.5gr pellet at 671fps, you would be generating 18.5 ft lbs of energy at the distance the pellet crosses the chrony. 

    As the pellet goes down range it will loose velocity and therefore energy. 

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    intenseaty22
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    Oh, man! You just learned me something new! That’s pretty cool.

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    DualMagMike
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    Many calculators online for fps=fpe the formula is velocity x velocity x weight then divide by 450240. 

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    sonny
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    He who asks a question is fool for the day but he who doesn't is fool for a lifetime. I believe  pyramyd air has a fps to ft/lb conversion chart free online.

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    OldFartFarmer
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    so after i calculate the different pellets,I do get the average and the spread,

    what am i looking for?

    and now ill go back and look for that magic number

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    OldFartFarmer
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    sonny

    He who asks a question is fool for the day but he who doesn't is fool for a lifetime. I believe  pyramyd air has a fps to ft/lb conversion chart free online.

    yes ive been using it,

    but im still confused on the information I have on the different pellets

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    JohnL57
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    My take is-shoot what groups tightest. A pellet that shoots with a very consistent speed SHOULD be accurate in your gun but paper does not lie…so test the most promising pellets at a distance when weather permits.

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    ackuric
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    The most important use (imo) from chronograph results are to calculate projectile trajectory, second being knowing your velocity spread (higher spread = larger groups the further out you shoot), and third, for tuning to a specific energy output. JMO! HTH

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    bubblerboy64
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    With your 97 the only thing you can do to affect velocity is to change the weight of the pellet.   In theory the pellet that shoots the most consistent velocity should be the most accurate.   I’ve got a chronograph it’s an aid in the search but honestly I shoot for accuracy and precision the velocity is just going to give me an idea of energy.  

    I set the chronograph as close as I can to the gun. Two reasons.  Muzzle velocity is typically the number used to compare. Secondly if the chrony is down range you will at some point hit it with a bullet.  Ask me how I know

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    fishinwrench
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    5 different chrony's will give you 5 different sets of numbers, so using one to determine true velocity for plotting trajectory is going to put you 1/2" to 2" off……which in THIS GAME is significant.

    IMO the only use for them (if you only use the same one all the time) is to compare readings after a "tune", or when comparing different pellets.  

    As far as I know the only way to ACCURATELY plot trajectory down to pinpoint accuracy is the old fashioned way…..shoot & measure.

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    sonny
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    Heavier pellets will generally have more energy down range and could possibly buck the wind better, although i have been shooting some lighter alloy pellets and getting impressive groups even in wind lately. 

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    CampFussell
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    fishinwrench

    5 different chrony's will give you 5 different sets of numbers, so using one to determine true velocity for plotting trajectory is going to put you 1/2" to 2" off……which in THIS GAME is significant.

    IMO the only use for them (if you only use the same one all the time) is to compare readings after a "tune", or when comparing different pellets.  

    As far as I know the only way to ACCURATELY plot trajectory down to pinpoint accuracy is the old fashioned way…..shoot & measure.

    Yup, that's the way I do it. The old fashioned way, shoot and record my holdovers for a given distance.

    John another thing the chrony is good for…..once you get your average velocity write it down somewhere for that particular gun and it's favorite pellet's weight. Then at a later date, say your groups don't look just right? Run a few shots across the chrony to make sure your gun hasn't lost any velocity from your original recordings. Would be a good way to see if there is a problem with the internals?

    I know on some of my PCPs, I write the avg velocity and pellet weight for each gun. Sometimes when I go to check a particular gun, say a few months or year later I might notice a slight loss in velocity and then I know to tweak the hammer spring adjuster to get her back on point with the original velocity.

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    OldFartFarmer
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    brian_null

    The "Magic Number" is 671… at 671fps the pellet weight in grains equals the foot pounds of energy. (slower = less, faster = more)

    (example) If you shoot a 18.5gr pellet at 671fps, you would be generating 18.5 ft lbs of energy at the distance the pellet crosses the chrony. 

    As the pellet goes down range it will loose velocity and therefore energy. 

    so when some on here send out there rifles, is this what they do when they say they tune it to a specific pellet?

    they find the 671fps for that favorite pellet 

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    brian_null
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    I wouldn't say that is the case… Its just that mathematically, when calculating the FPE, 671 happens to be the velocity that the weight works out so perfectly.

    So, if I'm shooting away and I see my chrony say that my last shot was at 900fps and I know I'm shooting 18.5gr pellets, I can easily see that I'm shooting quite a bit above 18.5fpe.

    Shoot groups with every pellet that you have. Find the 2 or 3 that group best at the distance you would normally shoot at. Pick your favorite and shoot a string of 20 shots. Record your velocity's and average them out. This will allow you to use an app like Chairgun (RIP) or Strelok to find your power curve for that pellet. This will give you better insight on your hold-over values for different distances when out in the field.

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    Wiseguy
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    ackuric

    The most important use (imo) from chronograph results are to calculate projectile trajectory, second being knowing your velocity spread (higher spread = larger groups the further out you shoot), and third, for tuning to a specific energy output. JMO! HTH

    X2!

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