.22 Long Rifle Wind Deflection ???

wallie

Which .22 Long Rifle would have the less wind deflection
A- Standard Velocity
B- High Velocity
C- Hyper Velocity

bgjohn

"A"

Tailgunner1954

A, IF your shooting distance is less than the distance required for the bullet to slow to trans-sonic velocity, past that the trans-sonic disturbance will cause more problem than the drift will.
Note that C will be more consistant (tighter groups) down range, even though it will be drifting/dropping further.

5mmgunguy

B or C depending on time of flight and the square area that the wind has available to influence.

dtknowles

If A and B have the same bullet then it is going to be a close call. B will have a shorter time of flight but A will have a higher ballistic coefficient due to lower mach number. A and B will be very close to the same drift. C will have more drift because of the much lower ballistic coefficient. The hyper velocity stuff has ligher bullets with big hollow points

Tim

bgjohn

"D"

sandwarrior

bgjohn Wallie,

"All the above"? [:D] The lightest weight will give the most wind drift at longer ranges. It will give less wind drift at short ranges. the same holds true with drop. The lighter faster bullet drops less at short ranges, the heavier bullets lose less velocity over range.

As for the trans-sonic barrier you will lose accuracy whenever a bullet comes through it. In the little .22's this happens pretty quickly. Before 100 yds is passed at sea level for a standard velocity. Right at or just after 100 yds for hyper velocity. However, the bullet never generated a huge shock wave so what shock-wave comes back over the bullet doesn't affect accuracy as much. It certainly won't affect accuracy as much as conditions will. Figure about 3-5 inches of drift for a 10 mph wind @100 yds. See where each bullet groups and there is your best answer.

wallie

dtknowles

Wallie

I don't know where you got that clipping but I think there are a couple things wrong with it.

First, in the first paragraph the author (unknown) starts our ok listing the three types of .22 rimfire in question but then in the second and later paragraphs he only use 2 examples not three. In his two examples he is not clear about which 2 of the three types of ammo he is really talking about.

Near the end he makes it sound like the .22 rimfire is a special case but in reality almost always when you reduce bullet weight to get higher velocity you end up with greater wind drift.

While the clipping is sort of correct the explanation is flawed. The bullets with lower ballistic coefficient will have greater wind drift. When you have two bullets with the same ballistic coefficient the bullet with the shortest time of flight will have the least wind drift.

Two identical bullets will have different ballistic coefficients if they are traveling at different velocity. These differences are greatest right around the speed of sound.

Tim

bpost

Precision Shooting Magazine had a very authortive multi-page math heavy article on the subject a couple of months ago. The subsonic round will indeed drift less. The transonic zone has a huge effect upon drift. The angle of wind on the point of the bullet at supersonic and transonic velocities has a much higher percentage of influence over wind drift than bullets traveling at subsonic speeds.