338 Winchester Magnum Load Data & Ballistics Calculator
Estimate chamber pressure and muzzle velocity for the 338 Winchester 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 Winchester Magnum reference
Maximum average pressure (MAP)
64,000 psi
Nominal case capacity
86.0 gr H₂O
Groove / bullet diameter
0.338 in (8.59 mm)
Example simulation illustrative
Bullet
Hornady 0.338 225 gr InterBond
Powder
IMR 4350
Charge
62.9 gr
Barrel
24 in
Muzzle velocity
2,594 fps
Peak chamber pressure (interval, ±10% burn rate)
40,077 – 49,980 – 61,067 psi
nominal is 78% MAP (64,000 psi)
Illustrative example — every figure is an estimate; always confirm your load against a current published manual before loading.
Popular 338 Winchester Magnum powders
Powders and bullets handloaders commonly use for the 338 Winchester 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 H4350
IMR 4350
Hodgdon H4831SC
Alliant Reloder 16
Alliant RL-19
Hodgdon H1000
Vihtavuori N560
Hodgdon Retumbo
Alliant RL-26
Alliant RL-25
IMR 7977
IMR 4064
Popular 338 Winchester Magnum bullets
Nosler AccuBond 338 Cal 225 gr Spitzer
Hornady 0.338 225 gr SST
Hornady 0.338 225 gr InterLock SP-RP
Barnes .338 225 gr TTSX BT
Sierra 338 Caliber (.338) 250 gr SBT GameKing
Barnes .338 210 gr TTSX BT
Nosler Partition 338 Cal 225 gr Spitzer
Nosler Partition 338 Cal 210 gr Spitzer
Sierra 338 Caliber (.338) 225 gr Spitzer Pro-Hunter
Nosler AccuBond 338 Cal 180 gr Spitzer
Sierra 338 Caliber (.338) 300 gr HPBT MatchKing
Sierra 338 Caliber (.338) 215 gr SBT GameKing
Speer Grand Slam GSSP .338 250 gr
Use MyLoads as a 338 Winchester 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.