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308 Winchester Load Data & Ballistics Calculator

Estimate chamber pressure and muzzle velocity for the 308 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.

308 Winchester reference

Maximum average pressure (MAP)62,000 psi
Nominal case capacity56.0 gr H₂O
Groove / bullet diameter0.308 in (7.82 mm)

Example simulation illustrative

Bullet
Sierra 30 Caliber (.308) 168 gr HPBT MatchKing
Powder
Hodgdon Varget
Charge
42.5 gr
Barrel
24 in

Muzzle velocity

2,648 fps

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

47,499 – 60,675 – 76,107 psi

nominal is 98% of the 62,000 psi maximum average pressure

This sample load runs near the maximum average pressure for the 308 Winchester (about 98% of MAP at the nominal estimate; the upper interval can exceed it). It is shown only to illustrate the simulator — reduce the charge and work up from your manual's start load.

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

Use MyLoads as a 308 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 308 Winchester in the MyLoads calculator →

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