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375 Winchester Load Data & Ballistics Calculator

Estimate chamber pressure and muzzle velocity for the 375 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.

375 Winchester reference

Maximum average pressure (MAP)52,000 CUP
Nominal case capacity48.0 gr H₂O
Groove / bullet diameter0.375 in (9.52 mm)

Example simulation illustrative

Bullet
Hornady 0.375 220 gr InterLock FP
Powder
IMR 4198
Charge
30.1 gr
Barrel
20 in

Muzzle velocity

1,909 fps

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

26,123 – 30,647 – 35,583 psi

maximum average pressure for this cartridge is specified as 52,000 CUP (CUP is not directly comparable to this psi estimate)

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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