<<Genesis93>> wrote:We could work it backward for you.... with the 25m of holdover (bullet drop), assuming a velocity of....what?? 1200fps.(guessing).. more?
What type of bullet, estimate of BC? Woodleight have a 440gr BP 510dia example with a BC of 0.255.... however;
A drop of 25m (984inch) translates to a BC of 0.317 based on 1200fps....
This trajectory is indeed rainbow-ish, near parabolic (though a bullet trajectory is asymmetrical really) and would be close to that of a rimfire 22...
<<Genesis93>> wrote:BC of 0.1 sounds a bit low... closer to a brick... made of foam..
in2anity wrote:<<Genesis93>> wrote:BC of 0.1 sounds a bit low... closer to a brick... made of foam..
Not really, think, 22 subs are 0.12 Besides isn't BC relative to MV anyway? (Lower the mv the lower the BC)
Noisydad wrote:Nope still cant get it to play nice but thats no surprise to me - its a computer thingy.
Here's some input info (all in Inches) for those interested enough to have a go:
55 grains 2F Black Powder (compressed)
Cast pure lead bullet, 450 grain,
Dimensions (as it leaves the barrel) Length 1.047
Land diameter .473
Groove diameter .507
Bore riding length .700
Ogive .347
Flat nose diameter .180
Barrel Length 36"
R.o.T. 1;36
<<Genesis93>> wrote:in2anity wrote:<<Genesis93>> wrote:BC of 0.1 sounds a bit low... closer to a brick... made of foam..
Not really, think, 22 subs are 0.12 Besides isn't BC relative to MV anyway? (Lower the mv the lower the BC)
BC has nothing at all to do with MV.... it is a function of the 'slipperyness' or inverse of aero drag, relative to a 'standard projectile'...
in2anity wrote:<<Genesis93>> wrote:in2anity wrote:<<Genesis93>> wrote:BC of 0.1 sounds a bit low... closer to a brick... made of foam..
Not really, think, 22 subs are 0.12 Besides isn't BC relative to MV anyway? (Lower the mv the lower the BC)
BC has nothing at all to do with MV.... it is a function of the 'slipperyness' or inverse of aero drag, relative to a 'standard projectile'...
Then how do you explain this:
https://www.sierrabullets.com/store/pro ... -170-gr-FN
(just as a example) scroll down to where it stipulates the BCs based on MV ranges. Not that I'm mathematical enough to really argue, I don't think it's quite as simple as you make it out to be. I might be wrong...
Not really, think, 22 subs are 0.12 Besides isn't BC relative to MV anyway? (Lower the mv the lower the BC)
<<Genesis93>> wrote:
lower mv = lower BC is absolutely not the case...as a generalisation...
If referring to specific projectiles and the slight variation over velocity - even your example has an increasing BC with reducing velocity....
<<Genesis93>> wrote:If the velocity is lowered to 1050 with the same drop, then the BC would be a lot higher than the 0.317 value...
Gamerancher wrote:I just ran it through the Hornady calculator online using 1000fps MV and got about a 21 yard bullet drop @ 600yards. Is that what we were after?