Reply To: Ballistic Coefficient for Kodiak Match .177

Forums Pellets, Projectiles, Slugs, & Ammo Ballistic Coefficient for Kodiak Match .177 Reply To: Ballistic Coefficient for Kodiak Match .177



Oldspook has given a good summary.
This morning Sept 3 in OZ I have taken the time to run some 10.65 gr Barracuda .177 Match past my Labradar radar chronograph from the RAW TM1000 benchrest gun with LW choked barrel. You may notice a trend as the velocity moves down further from Mach1.
Velocities are rounded; 19dC, 987 mB, 65%RH. Range from 0 yards to 23 yards
Vel;  BC (average from all data points of approx 2 per yard).
894;  .0198
872;  .0199
862;  .0204
857;  .0202
848;  .0203
843;  .0209
815;  .0209
813;  .0213
Playing with temperature inputs seems to indicate a BC increase of approx 0.0001 per dC.
# A different barrel and ambient conditions may give other results as most now know.
# There was a trend for the drag coefficient to peak at around 10 to 14 yards then reduce from there.  Stability may be best at  a longer range so BC average may be higher over a longer range. My research on .25 cal JSB Kings from a BSA barrel indicated average field tested BC still improved to 100 yards and to 200 yards as initial instability damped out.  … Other pellets at other velocities can become unstable beyond 40 to 50 yards and demonstrate spiral flight with deterioration of Cd and BC.

There are rough rules of thumb but no simple answers to simple questions in this game. The more I explore the more fascinating I find it to be.  …. Best regards, Harry.