Spin Doctor
Will that barrel stabilise that bullet? Miller twist rule, corrected for speed and air. Watch it wobble.
Default air is a cool Treasure Valley morning. Thin, hot air helps stability; sea-level winter hurts it. Air is the thing people forget when a load that was fine in August keyholes in January.
The curve is Sg against twist for this bullet, speed and air. The dot is your barrel. Green band is the comfort zone; below the red line the bullet does not fly point-first.
Miller: Sg = 30·m / (t²·d³·L·(1+L²)) with m in grains, d in inches, t and L in calibers, then × (V/2800)^⅓ × (T+460)/519 × 29.92/P. It assumes a conventional jacketed lead-core bullet; solid copper and very long plastic-tipped bullets read a touch optimistic, so give those more twist than the number says. Sg above 1.0 flies point-first; Litz puts the full-BC comfort zone at 1.5 and up. Not a substitute for shooting paper at 100.