MyLoads Open the calculator →

300 Lapua Magnum Load Data & Ballistics Calculator

Estimate chamber pressure and muzzle velocity for the 300 Lapua Magnum 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 Lapua Magnum reference

Maximum average pressure (MAP)4,400 BAR
Nominal case capacity113.3 gr H₂O
Groove / bullet diameter0.308 in (7.82 mm)

Example simulation illustrative

Bullet
Sierra 30 Caliber (.308) 220 gr HPBT MatchKing
Powder
Vihtavuori 24N41
Charge
78.7 gr
Barrel
27 in

Muzzle velocity

2,567 fps

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

50,312 – 58,867 – 67,624 psi

nominal is 92% of the 63,817 psi maximum average pressure

This sample load runs near the maximum average pressure for the 300 Lapua Magnum (about 92% 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 here is an estimate and can be wrong. Always consult a current published loading manual, and never trust these numbers on their own.

Open the 300 Lapua Magnum in the MyLoads calculator →

More cartridges