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358 Winchester Load Data & Ballistics Calculator

Estimate chamber pressure and muzzle velocity for the 358 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.

358 Winchester reference

Maximum average pressure (MAP)52,000 CUP
Nominal case capacity53.0 gr H₂O
Groove / bullet diameter0.358 in (9.09 mm)

Example simulation illustrative

Bullet
Hornady 0.358 250 gr InterLock RN
Powder
Accurate A-2520
Charge
38.6 gr
Barrel
24 in

Muzzle velocity

1,948 fps

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

22,142 – 28,671 – 36,104 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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