There are a couple of simultanous conversations going on this thread.
Conversation 1: Spin Energy and its effect on terminal performance.
The OP claims that the actual energy in the spin contributes to the bullet being more effective when it hits the target. It is a terminal performance issue and his claim has nothing to do with the trajectory of the bullet. He is claiming that the kinetic energy in the spin of the bullet will make the actual bullet strike more effective. While spin energy does exist, the energy due to spin is quite small and is not going to have any significant effect on the terminal performance.
In the example I worked out, changing the range to the target by 5 yards made more difference in the total kinetic energy of the round than the spin energy contributed.
Conversation 2: Spindrift and its effect on trajectory.
Spindrift is a gyroscopic effect that alters the trajectory very slightly in windage. It has no effect on terminal performance, it is purely a trajectory issue. It's not even a significant trajectory issue except at very long ranges when all other factors can be very accurately accounted for. Otherwise (as has been correctly pointed out by others) it's so small that other errors in estimating the trajectory will swamp it.
Conversation 1: Spin Energy and its effect on terminal performance.
The OP claims that the actual energy in the spin contributes to the bullet being more effective when it hits the target. It is a terminal performance issue and his claim has nothing to do with the trajectory of the bullet. He is claiming that the kinetic energy in the spin of the bullet will make the actual bullet strike more effective. While spin energy does exist, the energy due to spin is quite small and is not going to have any significant effect on the terminal performance.
In the example I worked out, changing the range to the target by 5 yards made more difference in the total kinetic energy of the round than the spin energy contributed.
Conversation 2: Spindrift and its effect on trajectory.
Spindrift is a gyroscopic effect that alters the trajectory very slightly in windage. It has no effect on terminal performance, it is purely a trajectory issue. It's not even a significant trajectory issue except at very long ranges when all other factors can be very accurately accounted for. Otherwise (as has been correctly pointed out by others) it's so small that other errors in estimating the trajectory will swamp it.
That is correct. This would actually be an effect of reduced spin and therefore reduced spin energy. So in that sense it's sort of the opposite of what the OP is claiming.