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44-40 Winchester Load Data & Ballistics Calculator

Estimate chamber pressure and muzzle velocity for the 44-40 Winchester with the free, in-browser MyLoads internal-ballistics simulator. The figures below are illustrative estimates from a physics model — not a recommended recipe. Always cross-check a current published loading manual.

44-40 Winchester reference

Maximum average pressure (MAP)11,000 psi
Nominal case capacity40.0 gr H₂O
Groove / bullet diameter0.428 in (10.88 mm)

Example simulation illustrative

Bullet
Hornady 0.427 205 gr COWBOY
Powder
IMR 800-X
Charge
5.9 gr
Barrel
20 in

Muzzle velocity

879 fps

Peak chamber pressure (interval, ±10% burn-rate)

9,391 – 9,971 – 10,521 psi

nominal is 91% of the 11,000 psi maximum average pressure

Illustrative example — every figure here is an estimate and can be wrong. Always consult a current published loading manual, and never trust these numbers on their own.

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