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Thread: pellet drop

  1. #1
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    Default pellet drop

    hi guys i was just wondering how you woyld work out pellet drop. sorry for the stupid questions im new to the sport
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  2. #2
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    Get a program called Chairgun. it does all the calculations for you and it is for free.
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  3. #3
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    Airsniper, I presume you are shooting HFT or hunting with your rifle in which case all you really need is to know where to point at various distances to secure a hit/kill!

    A very basic way of doing this would be to take a tape measure and place a box at all the distances between 10 and as far out as you feel you are accurate. I wouldnt bother hunting at distances greater than 45 to 50 metres anyway to prevent shooting bird's legs off and other horrible scenario's. You will probably find that you will be better off hunting inside 35 metres anyway especially if you have a springer and want to be pretty confident of a clean kill.

    I dont hunt but I,m sure the guy's who do will have something to say to correct me if I'm wrong on this.

    Back to the point, place the box at the distances at which you intend on shooting and obviously the box should have a target or targets attached to it so you can check your groupings and this should give you an idea of what is happening downrange and how much holdover or holdunder you need to apply. Take note also of the effects of shooting into the wing and with the wind because should the wind be strong you can expect eratic results and as such you will need to compensate. I usually compensate for wind by staying at home he he!!

    I hope this was in some way useful.
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  4. #4
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    thanx thats a great help, iv got chairgun but i dont know what fps my rifle is shooting at or anything si its quiet useless
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  5. #5
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    What rifle do you have and is it old or new?
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  6. #6
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    Airsniper,

    Here's a link explaining the mathematical theory, http://en.wikipedia.org/wiki/Trajectory_of_a_projectile

    Pellet drop, aka ballistic trajectory, can be determined determined in various ways, depending on what equipment you have at your disposal.

    The first way is when you have a rifle and a tin of the same pellets, but do not know what the pellets weigh or do not know what the muzzle velocity is (speed at which the pellet is traveling the moment it leaves the barrel). If this is the scenario, use the method described by Andrew, by physically learning via self discovery, what the pellet drop is for a specific pellet at predefined distances.

    The second way is when you basically know what the weight of the pellet is AND you know what the muzzle velocity is. Then you will be able to theoretically calculate the trajectory of a specific pellet. To measure the muzzle velocity of a specific pellet fired from your rifle you will need a chronograph. For general calculations you can use the weight printed on the tin ( Regarding weight, the weight printed on a tin should be regarded as a broad average weight, which is why you will tend to get an average grouping when putting theory to practice. For a more precise grouping, you will need to clean the pellets and sort them by measuring them each with a grain scale.) There are other factors too ( like ballistic coefficient, angle, etc ) and this is where you can finally play with ballistic applications like Chairgun, which do all the calculations for you and draw a nice visual graph/table for you. From this you can create a spreadsheet (cheat sheet) which you can use to determine/predict the pellet drop and appropriate scope adjustment for whatever range you're presented with. You will still need to spend time on a range like the one mentioned in the first method to confirm your calculations and to see what further offsets/calulations need to be made when firing under certain conditions (like down hill, windy, etc ). Also, in reverse, by playing with Chairgun you can determine trajectories for a specific pellet at different velocities, and then by using a chronograph. tune your rifle to a specific velocity.

    Note that I'm mentioning "specific pellet". What ever method you are using, you can only use one type/weight pellet, NEVER mixed.

    Hope this sort of helped too.


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  7. #7
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    shot. its a bsa airsporter s, its quiet old but its xtreemly accurate for a springer, and powerfull.
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