Did you look at the link that I posted? I thought that the physics/dynamics were described rather well.
The flight-time-in-a-vacuum is, in itself, irrelevant. What is important is the ‘delay’ (caused by the ballistic drag) of the pellet reaching the target. In a vacuum (or if the BC were infinite) then there would be no drag (and hence no deflection).
The sums work out like this :
Wind drift [Feet] = (s * sin(a)) * (t - (v/r)) … where:
t [seconds] = time of flight = 24000 * BC * (Exp(r / (8000 * BC)) - 1) / v
s = wind speed [in Ft/s]
a = angle of wind off trajectory path [degrees]
v = muzzle velocity [in Ft/s]
r = range [in Feet]
Note that the (v/r) term is the flight-time-in-a-vacuum so that (t – (v/r)) is equal to the ‘delay’ caused by drag. If the wind were at 90 degrees to the trajectory then (s * sin(a)) reduces to the windspeed since sin(90deg)=1
Dave
"Only two things are infinite, the universe and human stupidity, and I'm not sure about the former." Albert Einstein.
We had another bash it yesterday, shooting out to 100 metres. Same setup as before, 5 shots per group at 18 ft.lbs.
Results – I achieved groups between 2 -4.1 inches. A friend of mine tried it on my rifle and was achieving a consistent group of 2-2.3 inches with my rifle.How embarrasing
This leads to conclude that it is down to the shooters ability, because I could not get a consistent group at all yesterday and he did.
We are trying to get our hands on a 27 ft.lbs to see what results we can achieve. And will keep you posted.
Those of us of a certain age will remember when the four-minute mile was thought to be the very limit of human endeavour - 'impossible' they cried! Then, shortly after Roger Bannister achieved the ‘impossible’, a whole raft of athletes did it. Within ten years, the four minute mile equivalent was essential before a athlete could taken seriously. I reckon it’ll be like that with sub MoA groups at 100 and 150 yards – provided, of course, that that nice Gordon Blair (Tony Brown? ... whatever) and the rest of the knee-jerkers will let us keep our airguns long enough.
Better get practicing …
Dave
"Only two things are infinite, the universe and human stupidity, and I'm not sure about the former." Albert Einstein.
Heres a pic of the Pepsi bottle cap I shot several years ago with Career, 8 Bismags at measured 100yds, using a sandbag rest on bonnet of motor, the cap was trapped behind a bit of wire on a post
Very good, it all becomes clear!!!!
(Eye's become glazed, mouth slightly open, pen held to side of nose to try and show that he is listening, but in reality, the student is completely lost and hasn't the inclination to ask the lecturer to "repeat that bit again please")
AA 410k, 3-9X50
FN19 Hawke, 6-18x44
AA S200, 6-24X50
S10, 8-32X50
As I expected, and why I didnt put pic on the original thread
It was a concrete post that it was attatched to and by the time my mate (who also had identical Career) shot a couple of mags worth at a wine bottle cork in same place there was quite a bit of concrete missing
Admittedly it was an old post and a bit crumbly to start with but still not bad for an airgun
I remember chronoing the rifle in front of Terry Le Chem when TD brought him down a few years back I think it was doing 1030fps with Bismags
The link referred to earlier here makes it a lot clearer.
HTH
Dave
"Only two things are infinite, the universe and human stupidity, and I'm not sure about the former." Albert Einstein.
.177" Harrier X, Hydrographically dipped with custom FT Stock. .22" S410k BTAS with walnut thumbhole stock. .223 Tikka T3 Stainless Lite. CZ Varmint 17hmr. Browning and Baikal O/U 12g.
maybe a silly question, but isn't the air thinner at night? (less resistance), just before sun down?
Are you likely to get better groups long range without a silencer?