fnuser wrote: |
twist was 1-10 but I think you are missing my point stability inside an animal is improbable to predict. |
fnuser, thanks for the additional details. I ran the stability factor numbers for this bullet/cartridge combination. I assumed a cool day and 3100 fps velocity based on Barnes load data. I was surprised to see the resultant stability factor. The shorter TSX is just below the minimum recommended of 1.4 and the TTSX is really not stable enough. I'm amazed how much the small increase, 0.075 inches, in bullet length affects stability. The 100 gr .257 Tipped TSX really needs 1:9 twist or faster.
Caliber _ 0.257 Inches
Bullet Weight _ 100 Grains TSX
Bullet Length _ 1.113 Inches
Barrel Twist _ 10 Inches/turn
muzzle velocity _ 3100 fps
Temperature _ 45 degrees Fahrenheit (59 is standard)
Pressure _ 29.92 inches of mercury (29.92 is standard)
Stability Factor (Sg )= 1.37
Caliber _ 0.257 Inches
Bullet Weight _ 100 Grains Tipped TSX
Bullet Length _ 1.189 Inches
Barrel Twist _ 10 Inches/turn
muzzle velocity _ 3100 fps
Temperature _ 45 degrees Fahrenheit (59 is standard)
Pressure _ 29.92 inches of mercury (29.92 is standard)
Stability Factor (Sg )= 1.13
I'm can see your point that the terminal trajectory can not always be predicted. Based on the GSC experience, a stability factor 1.4 or greater is recommended if a hunter wants some predictability in how the bullet travels along its trajectory after impact. For the .25-06, a lighter (shorter) Barnes bullet would have higher stability