Estimate chamber pressure and muzzle velocity for the 243 Winchester 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.
243 Winchester reference
Maximum average pressure (MAP)
60,000 psi
Nominal case capacity
54.5 gr H₂O
Groove / bullet diameter
0.243 in (6.17 mm)
Example simulation illustrative
Bullet
Nosler Partition 6mm 95 gr Spitzer
Powder
IMR 4350
Charge
39 gr
Barrel
24 in
Muzzle velocity
2,893 fps
Peak chamber pressure (interval, ±10% burn rate)
39,486 – 48,367 – 58,150 psi
nominal is 81% MAP (60,000 psi)
Illustrative example — every figure is an estimate; always confirm your load against a current published manual before loading.
Popular 243 Winchester powders
Powders and bullets handloaders commonly use for the 243 Winchester, 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
Hodgdon Varget
IMR 4350
IMR 4831
Hodgdon H4831SC
IMR 4064
Alliant RL-22
Vihtavuori N165
Alliant RL-15
Hodgdon H380
Hodgdon H4895
Hodgdon H1000
Popular 243 Winchester bullets
Nosler Ballistic Tip Hunting 6mm 95 gr Spitzer (Purple Tip)
Hornady 0.243 95 gr SST
Nosler Partition 6mm 100 gr Spitzer
Sierra 6mm 243 Caliber (.243) 85 gr HPBT GameKing
Sierra 6mm 243 Caliber (.243) 107 gr HPBT-CN MatchKing
Berger 6 MM 105 gr VLD Hunting
Nosler Ballistic Tip Hunting 6mm 90 gr Spitzer (Purple Tip)
Nosler AccuBond 6mm 90 gr Spitzer
Nosler Ballistic Tip Varmint 6mm 70 gr Spitzer
Hornady 0.243 58 gr V-MAX
Speer Grand Slam GSSP .243 100 gr
Barnes .243 80 gr TTSX BT
Berger 6 MM 95 gr Classic Hunter
Use MyLoads as a 243 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.