Does anyone know of a formula for calculating FPE for a given projectile, if I know the weight and velocity ?? Is there an app or something I can use?/ I have a basic Caldwell chrono, but it only displays speed. I'd like just a bit more info.......Thanks !!
chronograph question
- Thread starter erock
- Start date
(g*v*v)/450240=FPE
g=grains
v=velocity fps
Ex:
(15.89*671*671)/450240 = 15.89
671 is a "magic" velocity because at that velocity you get 1 fpe per grain.
450240 is a constant derived from the long form of the calculation which considers the acceleration due to gravity of a body falling in free space. Just memorize it.
g=grains
v=velocity fps
Ex:
(15.89*671*671)/450240 = 15.89
671 is a "magic" velocity because at that velocity you get 1 fpe per grain.
450240 is a constant derived from the long form of the calculation which considers the acceleration due to gravity of a body falling in free space. Just memorize it.
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Aint no one got time for math and plot every engery. Lol. Last time I did a math problem was 20 years ago.
I use this. You enter your grain and fps and it will tell you both your ft lb and joules.
https://www.pyramydair.com/article/What_is_Muzzle_Energy_August_2003/5#:~:text=A%20velocity%20of%20671%20f.p.s.,%2Dgrain%20(142.86%20lbs.)
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Google Play Store has free apps for that (fpe calculator airgun). Just enter fps & projectile weight.
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It looks like someone "ain't got no time for readin', writin' or cipherin' ", there bubba. 
Meh.. see below.
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It is basic math, after 25 years of teaching community college, I have come to realize how few school graduates can do basic math or even read !! One of the classes I taught was a basic math class, did it for 3 years, every student was a high school graduate !!! Barely 60% passed, most students were under 25 yrs of age!!! The older guys over 50, actually did much better....shows how far our schools have came over the years !! Now picture all these folks with a pocket full of credit cards !!
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God help them if they receive instructions in cursive writing !! Thanks for all the VERY helpful tips in answer to my questions. Oh....yes, I still am able to read AND perform advanced math calculations as a retiree. Only as needed these days though. For now, will go with P/A basic calculation table. Just need approximate values. Not looking to make the sequel to the movie "Hidden Figures". Hahahaha If you've seen that movie, you'll understand. Have a great week !!
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My Pro Chrono DLX shows FPE on the shot string after entering your all projectile data. Otherwise, +1 on Pyramid Airs' calculator online.
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G P Conway wrote and published a full ballistic suite for airgunners.
Free.
Simple, intuitive, with brief instructions.
It offers all kinds of cool calculations, even those you didn't even know you needed...! (Seriously, very cool.)
He has them all on his webpage, and you can go to the respective app stores to download the mobile versions as well.
It also works on Windows, iOS, and even Linux.
Seriously cool.
Link: https://gpc.fotosoft.co.uk/Home.html
Matthias
Free.
Simple, intuitive, with brief instructions.
It offers all kinds of cool calculations, even those you didn't even know you needed...! (Seriously, very cool.)
He has them all on his webpage, and you can go to the respective app stores to download the mobile versions as well.
It also works on Windows, iOS, and even Linux.
Seriously cool.
Link: https://gpc.fotosoft.co.uk/Home.html
Matthias
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This is the one I use often, simple and quick.
Remember your FPE will not be exact no matter what number you put in the calculator, it will be a reference or a generalization. All chronographs give different speeds. For example the prochrono is about 10-15 FPS slower then FX pocket.
Remember your FPE will not be exact no matter what number you put in the calculator, it will be a reference or a generalization. All chronographs give different speeds. For example the prochrono is about 10-15 FPS slower then FX pocket.
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