trajectory calculations
i'vebeen looking on the web for the equations i need to find trajectories at different ranges but everything i've seen has basicly been serious bs if any of you could help me with this i would apreaciate it, thx ~Joe~
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For what cartridge or caliber? What equations do you need? All the major bullet/cartridge manuf. have ballistic charts on their website, I might be misreading your post. We can help but might need more info. 0 -
If I understand your question correctly you are asking for the equations used to figure the trejectory.
These can be found in any first year physics text book. (collage or high school) The ballistics charts you see on line have put these in play behind the numbers. If the 'why' is what you are after it is just to much for one post. You need the book![:D]
Time of flight is figured using the drag and that is shwon in relation to the acceration of gravity (32 fps/ps) and thus you have it.[8D]
Self defence is an ablsolute and natural right. Keep your powder dry! J. Rau, Alaska0 -
IMHO, find or buy a decent ballistic calculator.
While some basic hand calculations can be performed, they will not begin provide or approximate the data from modern load tables or modern software. Developing any type of trajectory or useful ballistic tables by hand is impossible. For one thing hand calculations cannot account for the enormous number of time steps which is essential for calculating the coordinate of the bullet during the flight time. Hand calculations will not account for temperature, pressure, humidity, or altitude and if wind drift, or uphill or downhill firing nor will hand calculations be able to account for the affect of gravity which is a function of altitude. If you think about, not having good ballistic solution was the major detriment to accurate artillery fire until about WWII when the US Navy installed the first "fire resolution" computer aboard battleships.
All good ballistics tables today use complicated differntial equations of motion called "Numerical Integration by Finite Interval". Using this method, real data inputs (temperature, pressure, altitude, etc.) and a modern PC, modern exterior ballistics software will provide a very exact answer.
There many exterior ballistics programs on the market today. Personnally, one of my favorites is "SHOOT" by Remington.
http://www.ballistics-software.com/shoot.htm
This is the link to download a version of the program and it is a very good freeware program. Another good ballistics program is RCBSLOAD. You can check out the link below for a variety of exterior ballistic software sold by Midway.
http://www.midwayusa.com/esearch.exe/search?TabID=0&category_selector=all_products&search_keywords=software&Click+to+Begin+Search.x=8&Click+to+Begin+Search.y=6
Regards,
Heavyiron
"If I don't see you nomore on this world, I'll meet you on the next one, and don't be late!" - Jimi Hendrix0 -
I think the other JR[8D] wanted some 'why' answered. All of the things you said are correct but are an over complication for a rifle shooter. You may want to note that no ballistics program will give you the exact path. You must shoot your load at two or more known distances and back the BC out of this info to get the true flight path.
Self defence is an ablsolute and natural right. Keep your powder dry! J. Rau, Alaska0 -
The programs do work, but you have to do a lot of tunning. For starters the BC as given by the manfacture is baised on a G1 drag form, while most modern bullets should use the G5 or G7 numbers. Also the BC number given isn't perfect, but off slightly (usualy in the third or fourth decimal). Atmospheric conditions must also be compinsated for, as well as the actual MV under those conditions. Another downfall of the programs is the interval between calculations, the greater the interval (some use 1 foot, some use 10yard intervals) the larger the stacked error becomes.
Bottom line is that the programs will get you close, but it takes actual firing (at actual distance and conditions), to plot the curve correctly (the results of long range firing is what allows you to accuratly tweek the input variables so that the output curve matches what your actual curve). All of the above assumes you have a rifle/load that is capable of grouping (repeatability of the initional curve).
Some guys like a mag full of lead, I still prefer one round to the head.0 -
I use the Sierra Infinity ballistic program on CD Rom. It has an infinite number of adjustments for wind, environmental conditions ( altitude, humidity), this thing works great. 0 -
I hate to resurrect this post.
Agree. The ballistics programs can get you very close but actual firing is required to ground truth the load/rifle and fine-tune the combination.
A note with regard to ballistic coefficients. Many regard a ballistic coefficient (BC) as a constant value based solely upon the properties of the bullet. This is partially true, but it should be noted that he BC is not constant but is dynamic -that is the BC will change based also upon atmospheric conditions and must be adjusted for the trajectory to be calculated. All the BCs that usually appear in the ballistic tables are standard values. They are calculated for sea level (0 feet elevation), 59 F, 79% humidity, and 29.53-inches of Hg. As such, these are the only conditions those BCs are valid. Change the altitude and the BC changes. Change the temperature and the BC changes etc.
Regards,
Heavyiron[8D]
"If I don't see you nomore on this world, I'll meet you on the next one, and don't be late!" - Jimi Hendrix0 -
quote:Originally posted by JR1
i'vebeen looking on the web for the equations i need to find trajectories at different ranges but everything i've seen has basicly been serious bs if any of you could help me with this i would apreaciate it, thx ~Joe~
Sorry, JR. Hate to rain on your parade, but the "simple" answers you seek do not exist to the degree you seem to want.
While there are many "constants" that you can depend on, there are also a few "variables" that consistently will throw your calculations off if not accounted for.
You might consider this explanation as "serious bs" if you wish, but to oversimplify something laden with so many variables would be irresponsible.
Many consider these calculations as something within a sliding scale with the precision and "stability/reliability" increasing with bullet's weight, in relation to these variables.
Once you understand these "basic" formulas as have been illustrated here in this thread, then the only ingredient needed to "join" the "club" is actual "trial" experience to develop your own "sixth sense" or whatever you wnat to call it. Good luck.
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"If it ain't broke, fix it anyway... make it better!" (RadCat)0 -
jr1,
I have no set formula. But, if you want some practical practice on line go to www.shooterready.com. There you will find a ten scenario sniper training demo using three different calibers. But, is useful to anyone who shoots long range for anything. You will then have to go to the different sites and figure out what works for your rifle/load.
I personally go to sst's rifle room(or www.sst-benchrest.com) There is a ballistic calculator on it that is pretty close to what I get out in the real world. I take that info and print it onto a range card and take it with me for where I shoot and make adjustments as needed. -good luck
We have the second amendment so that all the rest are secure....UNK>0
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