WebThe Greenhill formula was widely used for many decades, but the Miller formula for bullet stability has been shown to be more accurate and widely applicable for supersonic flight. … Web7 jan. 2009 · It is the "Greenhill Formula". Twist = 150 X D²/L With a bullet length of 1.15" Example: 150 X (.512 X .512)/ 1.15 =35.7 rounded 36:1 twist rate With a .9" bullet length …
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http://www.meplat.com.au/index.php/technical-information/ammunition-techncal-information/32-proj-stability Web2 feb. 2024 · To calculate twist rate using Greenhill's formula: Divide the specific gravity, SG of the bullet by 10.9. Find the square root of the resultant. Multiply the resultant with constant C, 150, and the square of the projectile diameter, D. Divide the product by the length of the projectile L to get the twist rate in inches per turn, t. cricket fq
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Web24 nov. 2024 · A Sierra Spitzer Boattail .243 bullet measures 1.0795", Using a modified Greenhill Formula, it needs at least a 1 in 10" twist if the MV gets below 2800 fps. Increasing the MV increases stability, since the bullets is … WebFormula. Invariant parameters. Variant parameters. Drag force D f = 0.5 ρ f S U 2 C D ρ f S, U, C D Fick’s law J i = –Di(dCi/dx) D i C i, x Beer’s law A λ = ɛ λ C s x ɛ λ, C s x Hagen–Poiseuille J w = –(π/8µ)(ΔP/l)r 4 µ ΔP, l, r Bending moments Due to gravity M b = 0.5 g ρ b V L sin φ g ρ b, V, L, sin φ Due to wind M w ... Web28 sep. 2015 · Using the following modified Greenhill Formula calculator, this bullet (1.219” long x .360” dia) will stabilize in a 35 Whelen with a 1 in 16 twist at 1800 FPS. A … budget analyst training courses online