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Old November 16, 2015, 08:29 AM   #26
tpcollins
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Thanks emcon5, I'll set the first drop column to "inches" and the second column to "MOA or MIL" depending on which scope I use.

Stag - good read on that link, thanks.
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Old November 16, 2015, 08:45 AM   #27
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Yep, Path is what you want. Drop is pretty much useless.
I'm not a math guy--but I believe theoretically you should be able to calculate muzzle velocity and consequently a ballistics table if drop at a known target distance is known--definitely useful if you have unknown ammo and no chrono--no?
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Old November 16, 2015, 10:13 AM   #28
emcon5
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I'm not a math guy--but I believe theoretically you should be able to calculate muzzle velocity and consequently a ballistics table if drop at a known target distance is known--definitely useful if you have unknown ammo and no chrono--no?
Sure, if you can make your rifle perfectly level, at a known distance above sea level, then have the target at the exact same distance above sea level.

Or, you could zero the rifle at 100 yards, then shoot at a farther distance and see how much the actual drop is. You can then tweak the velocity in the ballistic table until the prediction matches the measured results.
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Old November 17, 2015, 02:43 AM   #29
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I'm not a math guy--but I believe theoretically you should be able to calculate muzzle velocity and consequently a ballistics table if drop at a known target distance is known--definitely useful if you have unknown ammo and no chrono--no?
If you assumed a vacuum, yes. The assumption there is that the bullet speed is a constant and equals muzzle velocity*. The reason you could do the math in this case is because you know exactly how long it takes the bullet to drop the known distance, so you can calculate flight time to target. Because of no air resistance and the assumption of constant bullet speed, you can calculate the velocity, and therefore the trajectory. I believe calculus would be needed to do this simple (and useless) model.

I have to think it would be way more useful, and far more fun, to just go to the range and see where the bullet hits when you pull the trigger. I know that for me, it doesn't mean a hoot if the ballistics table says there's a 10" drop at 200 yards when zeroed at 100, if my group at 100 is already 4". I can't predict squat at 200, except the group size surely won't be smaller than 8".

*Muzzle 'velocity' is kind of an unfortunate term, because what we really mean when we use it is bullet speed at the muzzle. 'Velocity' specifically means the combination of speed (feet per second, for example) and direction. It's an important distinction when talking calculations, models and math...not too important when talking about shooting and hitting something.

Where the distinction IS important is when it's important to know that some force has to be applied to anything to change its velocity...even if its speed doesn't change. An example that's easy is a kid sitting on a merry-go-round, being spun at constant rpm by his associates. His speed isn't changing...but his velocity definitely is. That change in velocity is why he has to 'hang on'...it takes force to change velocity, and one way to change velocity to change the direction of motion--regardless of any change in the speed of that motion.
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Old November 17, 2015, 08:33 AM   #30
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I have to think it would be way more useful, and far more fun, to just go to the range and see where the bullet hits when you pull the trigger. I know that for me, it doesn't mean a hoot if the ballistics table says there's a 10" drop at 200 yards when zeroed at 100, if my group at 100 is already 4". I can't predict squat at 200, except the group size surely won't be smaller than 8".

That's funny bongo - makes sense to me!
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