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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 load. Always cross-check a current published loading manual.

358 Winchester reference

Maximum average pressure (MAP)52,000 CUP
Nominal case capacity57.0 gr H₂O
Groove / bullet diameter0.358 in (9.09 mm)

Example simulation illustrative

Bullet
Hornady 0.358 180 gr InterLock SP-SSP
Powder
IMR 4198
Charge
33.6 gr
Barrel
24 in

Muzzle velocity

2,242 fps

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

28,463 – 32,647 – 37,091 psi

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

The simulator isn't optimized for this cartridge yet and may read pressure low.

Illustrative example — every figure is an estimate; always confirm your load against a current published manual before loading.

Popular 358 Winchester powders

Powders and bullets handloaders commonly use for the 358 Winchester, drawn from public discussion and listed most common first. They appear as the Popular group in the calculator's pickers. This is not a load recommendation — always check your load against a current published manual.

Popular 358 Winchester bullets

Use MyLoads as a 358 Winchester velocity and pressure calculator: it estimates muzzle velocity, muzzle energy and the full chamber-pressure curve for your own powder, charge and barrel length, compared against the reference facts above.

Open the 358 Winchester in the MyLoads calculator →

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