Broncazonk
When the 7mm talks: the conversation ends.
What is the lowest acceptable SF on a bullet?
Bronc
Bronc
Stability Factors : The Lowest 'Good' Number
- Thread starter Broncazonk
- Start date
Bryan Litz Ballistics
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Short answer: 1.3 to 1.4.
Long answer:
In theory, the gyroscopic stability factor,Sg) only has to be greater than 1.0 to achieve stability. However, there are practical reasons not to pursuit this as a practical Sg. First of all, the number has to be calculated,predicted) and several aerodynamic and mass properties of the bullet have to be estimated to make the calculation, so there will always be error in the calculated Sg.
Secondly, the Sg is affected by air density, which changes with air temp, pressure and humidity. Achieving Sg=1.0 in one specific condition would mean Sg<1.0 if the temperature falls by just one degree.,bad plan)
Experts agree that a 'margin of error' of around 0.3 to 0.4 is adequate to insure reliable stability under all shooting conditions.
Hope this helps,
-Bryan
Long answer:
In theory, the gyroscopic stability factor,Sg) only has to be greater than 1.0 to achieve stability. However, there are practical reasons not to pursuit this as a practical Sg. First of all, the number has to be calculated,predicted) and several aerodynamic and mass properties of the bullet have to be estimated to make the calculation, so there will always be error in the calculated Sg.
Secondly, the Sg is affected by air density, which changes with air temp, pressure and humidity. Achieving Sg=1.0 in one specific condition would mean Sg<1.0 if the temperature falls by just one degree.,bad plan)
Experts agree that a 'margin of error' of around 0.3 to 0.4 is adequate to insure reliable stability under all shooting conditions.
Hope this helps,
-Bryan
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