Fellas,
Here is a question for all of you long distance shooters out there.
Where can I find a formula to figure out bullet impact angle at a particular range?
I have the bullet trajectory but can't wrap my brain around trying to figure out the impact angle at the target.
44-40 Website - https://sites.google.com/view/44winchester/chasing-the-44-40
Attached Files
Fellas,
Where can I find a formula to figure out bullet impact angle at a particular range?
I have the bullet trajectory but can't wrap my brain around trying to figure out the impact angle at the target.
Well, it's either college level math and geometry or a Civil Engineer with access to Auto-Cad. You have listed one of the necessary things, but have not listed the other three.
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"In a vacuum," as they say, where the bullet's flight would be parabolic, it's the tangent to a parabola at impact.
(To be clear: I'm not talking about the projectile axis relative to the trajectory. Your holes look to be circular; I don't think you're asking about over-stabilization or keyholes, right?)
Since we're talking rifles under 300 yards and not artillery at 10 miles, let's ignore the "not a parabola" bit.
Relative to muzzle height, what are your downrange POI distances and heights for a single POA? All I got from your video is 17" down at 100 yards and 28-3/4" down at 265 yards -- and I'm guessing that the muzzle and POA are about the same height, right?
Computing the parabola requires three points. The elevations of three groups (25, 50, 100 yards, for example) fired from a rest with the barrel horizontal is a good starting point. POI will always be higher than zeroed POA when the barrel is tilted either up or down; that's a different calculation.
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(To be clear: I'm not talking about the projectile axis relative to the trajectory. Your holes look to be circular; I don't think you're asking about over-stabilization or keyholes, right?)
Since we're talking rifles under 300 yards and not artillery at 10 miles, let's ignore the "not a parabola" bit.
Relative to muzzle height, what are your downrange POI distances and heights for a single POA? All I got from your video is 17" down at 100 yards and 28-3/4" down at 265 yards -- and I'm guessing that the muzzle and POA are about the same height, right?
Computing the parabola requires three points. The elevations of three groups (25, 50, 100 yards, for example) fired from a rest with the barrel horizontal is a good starting point. POI will always be higher than zeroed POA when the barrel is tilted either up or down; that's a different calculation.
Yes sir, bullet is stable. I was planning on setting up two targets, one behind the other a few feet and just figure it out that way.
Thanks for taking the time to try and help.
Muzzle height should be typical benchrest height. I can get detail measurements later but I'd say about 42 inches from the ground.
Downrange POA (for right now) is 265 yards. The scope is zero at 200 yards. The 265 yard POA is 28 3/4 Higher than the bullseye or bullet impact area. However, the target is about 50 FEET LOWER lower (down hill) than the muzzle.
44-40 Website - https://sites.google.com/view/44winchester/chasing-the-44-40
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The barrel is pointing at the 200 yard target in this photo, the 265 is just to the left. You can see the decline in elevation to the targets
.
44-40 Website - https://sites.google.com/view/44winchester/chasing-the-44-40
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FWIW,
The quick an easy is to , as you mention, place two targets/cardboard about 6 feet apart at the range chosen,
carefully using spirit levels, etc you can measure the drop in the 6 feet and determine the angle of the bullet travel
at the target. Othewise, Enjoy the mathmatical challenge of figuring that Modified parabolic trajectory.
Dan Theodore had done this "six feet apart" empirical measurement at 1000yds to determine what was the safety situation for Black Powder Cartridge rifles
at that distance as the bullets came over the pits. The angle was something like 6 degrees. Not "like a mortar round" as
some people had envisioned. Also note the the BPCR bullets rise something like 46 feet in their trajectory over the thousand yards
beltfed/arnie
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The angle was something like 6 degrees. Not "like a mortar round" as
some people had envisioned.
beltfed/arnie
I was guessing less than ten degrees from what I have seen.
My brain hurts
44-40 Website - https://sites.google.com/view/44winchester/chasing-the-44-40
Attached Files
Hmm... I thought you were wanting something that would work at any range. If you're just wondering about one or two distances the "two targets, six feet apart" sounds like what you're after. My bad.
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Hmm... I thought you were wanting something that would work at any range. If you're just wondering about one or two distances the "two targets, six feet apart" sounds like what you're after. My bad.
Oh no, I am looking for a mathematical formula that will work at all ranges. Doesn't mean I will know how to use it, just hoping I can learn. So far I see nothing.
44-40 Website - https://sites.google.com/view/44winchester/chasing-the-44-40
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Oh no, I am looking for a mathematical formula that will work at all ranges. Doesn't mean I will know how to use it, just hoping I can learn. So far I see nothing.
And you won't see anything BECAUSE you're not taking the major variables into account. College level math and understanding what is happening with the setup you use is the key. Inclination and declination of the line of sight has a lot to do with it. Usually people here say "this isn't rocket science".... well, it is here..... beginning rocket science, but it still is.
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Oh no, I am looking for a mathematical formula that will work at all ranges. Doesn't mean I will know how to use it, just hoping I can learn. So far I see nothing.
And you won't see anything BECAUSE you're not taking the major variables into account. College level math and understanding what is happening with the setup you use is the key. Inclination and declination of the line of sight has a lot to do with it. Usually people here say "this isn't rocket science".... well, it is here..... beginning rocket science, but it still is.
So basically no one here can give me an example?
44-40 Website - https://sites.google.com/view/44winchester/chasing-the-44-40
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Variables influencing angle of impact:
Rifle setup, height of sights above center line of bore.
Sight in distance and accuracy of load.
Muzzle velocity and ballistic coefficient or complete trajectory of load
Angle of inclination or declination of line of sight or elevation of muzzle and point of impact
With military tracking radar, your answer is a data line, but someone with Auto-Cad could plot the trajectory line properly as it is in reality, construct a normal line at the point of impact then construct a perpendicular and query what it's angle is thereby giving you your answer. All this varies with angle of line of sight in the world.
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Variables influencing angle of impact:
Rifle setup, height of sights above center line of bore.
Sight in distance and accuracy of load.
Muzzle velocity and ballistic coefficient or complete trajectory of load
Angle of inclination or declination of line of sight or elevation of muzzle and point of impact
With military tracking radar, your answer is a data line, but someone with Auto-Cad could plot the trajectory line properly as it is in reality, construct a normal line at the point of impact then construct a perpendicular and query what it's angle is thereby giving you your answer. All this varies with angle of line of sight in the world.
This is mind blowing stuff. Evry time I think I find something, it is just a formula to find a formula to find another formula...lol
Bullet is fired from a muzzle 45 inches above the surface.
Bullet is traveling at 1,478fps.
Bullet decelerates to 951fps impact velocity at 265 yards Bullet weight is 215 grains
Bullet impacts a vertical target 24" above the ground
Elevation difference from point of origin to impact is -58 feet, from 1,241 feet at the muzzle to 1,185 feet at impact, plus the 2 foot gain in elevation at impact on the target.
Muzzle angle is unknown, line of sight is level from the muzzle to 200 yards, plus 28 3/4" at 265 yards
Bullet trajectory's are approx. and can be corrected later...I think. I do not have exact data with me.
muzzle to 25 yards = +5 inches
muzzle to 50 yards = +8 inches
muzzle to 100 yards = +14.5 inches
muzzle to 125 yards = -- inches
muzzle to 150 yards = +10.5 inches
muzzle to 175 yards = -- inches
muzzle to 200 yards = + 0.5 inches
muzzle to 225 yards = -13 inches
muzzle to 250 yards = -- inches
muzzle to 265 yards = -28 3/4 inches I am hoping the angle at impact is less than 10 degrees. My plan is to set up two targets, one 6 feet behind the other and simply measure the different elevation of the impact holes of each target. I'd like to know the scientific method ;-) Still searching...
44-40 Website - https://sites.google.com/view/44winchester/chasing-the-44-40
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I'll be gone or very busy for the next three days, but will plot this out in the real world and see what happens.....You have given enough information to work it out. Stay tuned.
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I'll be gone or very busy for the next three days, but will plot this out in the real world and see what happens.....You have given enough information to work it out. Stay tuned.
Awesome!
44-40 Website - https://sites.google.com/view/44winchester/chasing-the-44-40
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while my mind is boggling from the above discussions, it is interesting ( or not ) that since the bullet at 140,000 rpm is gyroscopically stabilized with respect to the universe ...
if you shot it fast enough to put it into low earth orbit ...
at 1/4 around the earth it would appear to an observer there to be traveling with point straight up ...
halfway around the earth the bullet would zing by an observer's ear going base first ...
*************
and now for some useful information ... somewhere on the internet you can download for free Dr. Mann's book on his experiments .. been a few years, but i think Bullet's Flight is the link.
i have read his book 6 times ... it still wears me out about half way through ... heh ...
ken
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while my mind is boggling from the above discussions, it is interesting ( or not ) that since the bullet at 140,000 rpm is gyroscopically stabilized with respect to the universe ...
if you shot it fast enough to put it into low earth orbit ...
at 1/4 around the earth it would appear to an observer there to be traveling with point straight up ...
halfway around the earth the bullet would zing by an observer's ear going base first ...
*************
and now for some useful information ... somewhere on the internet you can download for free Dr. Mann's book on his experiments .. been a few years, but i think Bullet's Flight is the link.
i have read his book 6 times ... it still wears me out about half way through ... heh ...
ken
If I don't stop reading it, my brain is going to explode!! I don't think much of his information is really useful....I just like reading about the "things" they use to do back in the day.
I found a 1947 publication for $15....couldn't pass it up.
44-40 Website - https://sites.google.com/view/44winchester/chasing-the-44-40
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Mann's work is the bases for all 20th century work on cast bullets. Without that background, you are reinventing the wheel. If it takes ten times to understand it, you had better do it. Or else Mattern, Sharpe and Pope will mean nothing.
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Mann's work is the bases for all 20th century work on cast bullets. Without that background, you are reinventing the wheel. If it takes ten times to understand it, you had better do it. Or else Mattern, Sharpe and Pope will mean nothing.
I figured that would get someone's attention!!!!!!
44-40 Website - https://sites.google.com/view/44winchester/chasing-the-44-40
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44-40 215gr bullet impact angle example at 265 yards. 951fps.
Angle don't look too bad huh? Any error in the chronograph angle would just increase the velocity.
44-40 Website - https://sites.google.com/view/44winchester/chasing-the-44-40
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Best I can tell from my research from two days, a gyroscopically stable bullet will be perpendicular to the the center of mass of the earth after it reaches to apex of launch flight. FWIW
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wimilkman
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Aaron
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porthos
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