Wind fight factor.

[Emu]

So is your theory that for example, the JSB .30 cal 50.1 drifts less in the wind than say the JSB .25 cal King Heavy? Even though the King Heavy has a BC significantly higher than the 50.1 grain JSB? And are you disagreeing with Bob Sterne's statements below?

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When you shoot in a crosswind, the pellet drifts sideways, causing your POI to be downwind of your POA. The largest factor governing the magnitude of this drift is the BC.

There are many misconceptions about wind drift, the biggest being that “time to target” is the key. That is NOT the case. The wind drift is proportional to the DIFFERENCE in the actual time of flight, compared to what it would be in a vacuum. This is called the “lag time”.

This is a difficult thing to wrap your brain around, and even harder to explain without involved mathematics, so I will leave to you Google it if you don’t believe me. However, it is a fact that we have to deal with when considering the external ballistics of diabolo pellets.

Since the lag time is the key, then how fast the pellet slows down (mostly governed by the BC) is the key. 

Surface in contact with wind is essential in the capture of the force of the wind (in fact that force moves the sail sailing ships).

Weigh attracted by gravity is the other force into equation.

Cars, planes and bullets are mostly designed to fight with weigh of air in the front because a reason: the projectile or object (car, plane and bullet) had more speed that (thanks God) the wind normally reach.

A plane has a speed or 800 km/hr, a terrifying huracan could eventually reach 220 km/hr.

So cars, planes and bullets are designed to "penetrate" easier on air (aerodynamic).

My understanding is that BC measures aerodynamic of the bullets to determine the efficiency in penetrating the air and to try to know how much compensation you need in a parabolic trajectory in order to hit the target. All considering a front fight with wind.

What this thread try is to understand is why (as we have experienced) .177 Cal is much more influenced by wind at long range that other larger calibers.

 

[Emu]

Look at what Arzrover said today in his comment at 9:21 Am in the treath ". 177 VS.. 25 practical trajectory":



"the farther you shoot, the more difference the higher bc on the 22 will make. The bc is an expression of the amount of drag experienced by the projectile. Not all 22 pellets are higher than all 177. If you look on JSBs web site, they have a chart of all the pellets they make with their respective bc. At 50 yds, my ballistic app shows 0.8 mils of drop for the 18.1s and 0.9 mils for the 10.34s. At 100 yds, it's 4.8 mils for the 18.1s and 5.2 mils for the 10.34s. At 100 yds , a 10 mph wind would blow the 18.1s 3.5 mils and the 10.34s would blow 4.1 mils. A mil is approximately 3.6 inches . 

Bob"