Is Faster or slower generally best?

[mdeland]

Not really, the faster most accurate load your rifle can shoot will always be an advantage ballistic-ally for deflection and vertical. It's just that from a practical stance accuracy trumps the other considerations, especially in calm air, which is very rare.
I still think the big 38's have a vast untapped potential for long range work that has not been fully realized.

[mdeland]

Sierra says more speed less wind deflection because time of flight is reduced all else being equal course they are talking jacket bullets that start super sonic. At 1K most of those bullets are in transonic near the target. I doubt the lead bullet reacts much differently to ballistic physics than would comparably shaped jacket bullets at the same velocities.

[art ruggiero]

we are not shooting the extremly hi bc bullets at 3000fps that they are speaking of art

[mdeland]

Or it could be that a long held belief that the slower bullets have less deflection is incorrect ! Actually, just as more speed makes less vertical it would also follow logically that the less time a cross wind can work on a bullet the less it would deflect. Just as gravity plays a large part in the vertical so also does the direction of bullet spin play a part on deflection. It is said that the spinning bullet turns into the wind but it actually turns with the wind and there is a small difference in deflection if the cross wind blows into the bullet rotation or away from it. There is also a vertical component, the two working in combination I would think becomes spin drift.

[mdeland]

I should add that when the cross wind blows into/against the direction of spin the bullet rises and when away/with rotation, it lowers. Horizontal deflection is greater when blowing with bullet rotation.

[mdeland]

I should have said that the two wind components working together seem to become part of spin drift as the bullet nose angle is altered in the direction of spin.

[Kurt]

I was reading a report on this subject once but I don't remember if it was from the Montana State University or from other old publishings that the shock wave of the ogive shape of a bullet in flight had the effect for the drift.

[beltfed]

Yes,
it is the shock wave that is "dragged" along with the bullet in the transonic region and above that has the
greater wind deflection effect that very gradually decreases as the velocity goes up to the +- 2000fps level.
A person can easily see this effect when looking at trajectory tables for Hi Speed/ .22 LR vs Std velocity/subsonic 22 LR.
The subsonic ammo will have less wind deflection. Pretty much Mos ALL Target, precision 22 ammo is loaded to slightly subsonic
velocity for the best accuracy as the "buffeting" dragged along sonic shock wave of slightly supersonic ammo is not the best thing for
accurate flight.
beltfed/arnie

[mdeland]

My guess Arnie is the faster cartridges are shooting a lighter bullet with a different nose shape and less BC.

[desert deuce]

Does momentum calculated with bc and rate of spin figure into the calculations?

Seeing that the .22 rimfire at 300 yards has similar drift to a .45 caliber bullet at 1000, or so I have heard. I have not laid down on the mat to explore it but do see potentially corroborating evidence when shooting at 200 yards.

Most of the .22 Match Ammo I have chronographed registers well below 1150 fps, most high velocity is near or above 1200 fps. The match definitely registers less ES extreme spread. In our .22 rifles the individual rifle will show a preference to a particular ammo over most others. Also see lot to lot differences of the same brand.

All leads back to at some point it is the shooter/rifle/ammo combination that determines results on the intended target. Let's face it, .22 silhouette is fun and available to anyone at any skill level at most any age and financial situation.

Wondering if a new shooter would be well served if they started with .22 silhouette, graduate to a 40-65 before jumping on a 45-90?

Just wondering?

[mdeland]

I have long felt that wind vectors react to the pressure envelope around a bullet in flight , not the actual physical bullet. It can be seen in high speed pictures manifesting as a bow wave and slip stream trailed by a boiling drag motion.

[J.Murphy]

mdeland,
I spent two years trying to shoot BPCR at slow velocity. It is true that the slower velocity ( 1090 fps) drifts less than a higher velocity ( 1300 fps), this is because of increased drag around the speed of sound. To test it, I fired the same bullet alternately fast and slow at the Rams in a steady crosswind, the faster bullet drifted about 12" more than the slower bullet. The problem is that at slower velocities the normal velocity variations translated into greater vertical dispersion. The wind drift was better during windy days, but the vertical issues were there every day. The faster velocities give less vertical dispersion, especially at long range.
John Murphy

[bruce m]

john,
you can learn to deal with wind deflection.
there is zilch you can do to overcome vert.
(other than change the load)
bruce.

[martinibelgian]

Meaning that yes, at short range (out to 300?), the subsonic bullet might have an advantage as to wind drift. But at longer range, the increased vertical will kill you.

[mdeland]

I think the big 38's might have an advantage with a hard alloy and high BC bullet if they could be run 1500 fps or better with BP.