338 Lapua Magnum Load Data & Ballistics Calculator
Estimate chamber pressure and muzzle velocity for the 338 Lapua Magnum 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.
338 Lapua Magnum reference
Maximum average pressure (MAP)
65,000 psi
Nominal case capacity
114.0 gr H₂O
Groove / bullet diameter
0.338 in (8.59 mm)
Example simulation illustrative
Bullet
Hornady 0.338 285 gr ELD Match
Powder
Hodgdon Retumbo
Charge
87.3 gr
Barrel
27 in
Muzzle velocity
2,534 fps
Peak chamber pressure (interval, ±10% burn rate)
39,032 – 47,300 – 56,338 psi
nominal is 73% MAP (65,000 psi)
Illustrative example — every figure is an estimate; always confirm your load against a current published manual before loading.
Popular 338 Lapua Magnum powders
Powders and bullets handloaders commonly use for the 338 Lapua Magnum, 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.
Hodgdon Retumbo
Hodgdon H1000
Alliant RL-33
Hodgdon US 869
Hodgdon H4831SC
Alliant RL-25
Vihtavuori N560
Alliant RL-19
IMR 7977
Alliant RL-22
Vihtavuori N165
Alliant RL-26
Popular 338 Lapua Magnum bullets
Sierra 338 Caliber (.338) 300 gr HPBT MatchKing
Sierra 338 Caliber (.338) 250 gr HPBT MatchKing
Berger 338 Cal 300 gr Hybrid OTM Tactical
Berger 338 Cal 250 gr Hybrid OTM Tactical
Berger 338 Cal 250 gr Elite Hunter
Hornady 0.338 250 gr BTHP Match
Lapua Scenar OTM .338 300 gr
Nosler AccuBond 338 Cal 250 gr Spitzer
Nosler Partition 338 Cal 250 gr Spitzer
Nosler AccuBond 338 Cal 300 gr Spitzer
Barnes .338 285 gr TSX BT
Barnes .338 225 gr TTSX BT
Use MyLoads as a 338 Lapua Magnum 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.