Bryans book is great! He explains it in there. Wow does he know his stuff!!!
I believe when the bullet is early in its flight, the spin rate is as high as it is going to be. I think its slightly OVER STABILIZED. Of course depending on bullet type velocity/and twist rate. Every bullet has its physical characteristics/parameters. As the bullet travels down range the rotational speed slows down slowly, and fully stabilizes. According to its particular characteristics.
Here is my personal thoughts/ theories:
I was taught in trade school that every spinning element has natural "Frequencies". Such as a Power Turbine that spins at high rates of rpm.
these turbines (when started) have to be aggressivley accellerated up to its final rotational speed.
Because as the shaft crosses certain rotational speed rates, it hits what we call critical speeds. At these speeds, if the shaft is allowed to maintain these critical speeds for any real length of time, the shaft will destroy itsself.
I wonder if, as the bullet travels down range,(slowing down velocity and rotational speed) does the bullet encounter these critical speeds? (of course rotational speed slows much slower than velocity).
This would account for how some bullets will have some (larger spans of accuracy dispersion) Areas where stablity and accuracy fade in and out over the entire bullets flight.
Eventually as velocity drops down into, and through the transconic, and into the sub sonic speeds, the dynamic overturning torque becomes too great and the bullet finally looses all its stabilty and tumbles.(in some bullet designs). Some bullets travel through this critical area of velocity transition virtually unaffected. these bullets may travel much further before Dynamic overturning torque claims its stability. Every bullet style/design is different.
I dont know if I described that very well, but how does this approach sound to you gunnutz?
Take care and straight shootin!
Keep it fun!
I believe when the bullet is early in its flight, the spin rate is as high as it is going to be. I think its slightly OVER STABILIZED. Of course depending on bullet type velocity/and twist rate. Every bullet has its physical characteristics/parameters. As the bullet travels down range the rotational speed slows down slowly, and fully stabilizes. According to its particular characteristics.
Here is my personal thoughts/ theories:
I was taught in trade school that every spinning element has natural "Frequencies". Such as a Power Turbine that spins at high rates of rpm.
these turbines (when started) have to be aggressivley accellerated up to its final rotational speed.
Because as the shaft crosses certain rotational speed rates, it hits what we call critical speeds. At these speeds, if the shaft is allowed to maintain these critical speeds for any real length of time, the shaft will destroy itsself.
I wonder if, as the bullet travels down range,(slowing down velocity and rotational speed) does the bullet encounter these critical speeds? (of course rotational speed slows much slower than velocity).
This would account for how some bullets will have some (larger spans of accuracy dispersion) Areas where stablity and accuracy fade in and out over the entire bullets flight.
Eventually as velocity drops down into, and through the transconic, and into the sub sonic speeds, the dynamic overturning torque becomes too great and the bullet finally looses all its stabilty and tumbles.(in some bullet designs). Some bullets travel through this critical area of velocity transition virtually unaffected. these bullets may travel much further before Dynamic overturning torque claims its stability. Every bullet style/design is different.
I dont know if I described that very well, but how does this approach sound to you gunnutz?
Take care and straight shootin!
Keep it fun!
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