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300 WSM Load Data & Ballistics Calculator

Estimate chamber pressure and muzzle velocity for the 300 WSM 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.

300 WSM reference

Maximum average pressure (MAP)65,000 psi
Nominal case capacity80.0 gr H₂O
Groove / bullet diameter0.308 in (7.82 mm)

Example simulation illustrative

Bullet
Hornady 0.308 165 gr GMX
Powder
Hodgdon Superformance
Charge
60 gr
Barrel
24 in

Muzzle velocity

2,857 fps

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

33,312 – 46,235 – 62,034 psi

nominal is 71% of the 65,000 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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